U.S. patent application number 11/589621 was filed with the patent office on 2008-05-01 for heat pump system and controls.
This patent application is currently assigned to Electro Industries, Inc.. Invention is credited to William J. Seefeldt.
Application Number | 20080098760 11/589621 |
Document ID | / |
Family ID | 39328518 |
Filed Date | 2008-05-01 |
United States Patent
Application |
20080098760 |
Kind Code |
A1 |
Seefeldt; William J. |
May 1, 2008 |
Heat pump system and controls
Abstract
A heat pump system is disclosed that utilizes one or two
compressors and multiple heat exchangers to provide forced air
heating, radiant heating and/or water heating for an interior
space. A controller directs energy to these multiple system outputs
to provide maximum comfort, effectively utilize any excess energy,
address fluctuations in energy output, prevent unsafe operating
conditions and avoid intermittent compressor operation. The system
may provide energy for a water heater in both heating and cooling
mode, and control operation of the water heater to utilize system
energy whenever possible and avoid use of a conventional water
heater heating element. Load Management Control is also provided so
that the system may be shut down remotely by a utility company.
Inventors: |
Seefeldt; William J.;
(Monticello, MN) |
Correspondence
Address: |
DOWELL BAKER, P.C.
201 MAIN STREET, SUITE 710
LAFAYETTE
IN
47901
US
|
Assignee: |
Electro Industries, Inc.
|
Family ID: |
39328518 |
Appl. No.: |
11/589621 |
Filed: |
October 30, 2006 |
Current U.S.
Class: |
62/238.7 ;
62/160; 62/324.6; 62/510 |
Current CPC
Class: |
F25B 47/025 20130101;
F25B 1/10 20130101; F25B 2400/0401 20130101; F25B 2400/0403
20130101; F25B 2313/008 20130101; F25B 2313/02741 20130101; F25B
2600/0252 20130101; F25B 2700/21152 20130101; F25B 13/00 20130101;
F25B 2700/1931 20130101; F25B 2700/2104 20130101; F25B 2700/2106
20130101; F25B 2400/13 20130101; F25B 2339/047 20130101; F25B
29/003 20130101; F25B 40/04 20130101; F25B 2313/0234 20130101; F25B
2600/2509 20130101; F25B 2313/003 20130101; F25B 2700/21161
20130101 |
Class at
Publication: |
62/238.7 ;
62/160; 62/510; 62/324.6 |
International
Class: |
F25B 13/00 20060101
F25B013/00; F25B 27/00 20060101 F25B027/00; F25B 1/10 20060101
F25B001/10 |
Claims
1. A heat pump system including: a primary compressor; a first heat
exchanger; a second heat exchanger; a third heat exchanger; a
fourth heat exchanger; a conduit system connecting the primary
compressor, the first heat exchanger, the second heat exchanger,
the third heat exchanger and the fourth heat exchanger, the conduit
system circulating a refrigerant through the primary compressor,
the first heat exchanger, the second heat exchanger, the third heat
exchanger and the fourth heat exchanger; a first blower to direct
indoor air into heat exchange relationship with the first heat
exchanger to provide forced air heating or cooling for an indoor
air space; a second blower to direct outdoor air into heat exchange
relationship with the second heat exchanger to provide energy to
the system for heating or remove energy from the system for
cooling; a radiant heating system in heat exchange relationship
with the third heat exchanger to provide radiant heating for an
indoor space; a water heating system in heat exchange relationship
with the fourth heat exchanger to provide heating for tap
water.
2. The heat pump system of claim 1, the heat pump system further
including: a booster compressor connected to the conduit system,
the conduit system also circulating the refrigerant through the
booster compressor.
3. The heat pump system of claim 2 wherein the primary compressor
and the booster compressor are connected in series by the conduit
system.
4. The heat pump system of claim 3 wherein the conduit system
includes a booster compressor bypass section so that the primary
compressor may be selectively operated without the booster
compressor or in series with the booster compressor.
5. The heat pump system of claim 1, the heat pump system further
including: a controller; the radiant heating system including a
first pump to circulate a fluid in heat exchange relationship with
the third heat exchanger; the water heating system including a
second pump to circulate a fluid in heat exchange relationship with
the fourth heat exchanger.
6. The heat pump system of claim 5 wherein the controller
selectively operates the first blower, the first pump and the
second pump in response to the heating needs of the indoor air
space.
7. The heat pump system of claim 5 wherein the controller operates
the first pump to provide radiant heating for the indoor space but
deactivates the first pump when heat is needed for the indoor air
space.
8. The heat pump system of claim 5 wherein the controller operates
the second pump to provide heating for tap water but deactivates
the second pump when heat is needed for the indoor air space.
9. The heat pump system of claim 5, the heat pump system further
including: an indoor air thermostat; the controller including an
internal timer, the controller starting the timer and activating
the primary compressor, the first blower and the second blower upon
receipt of a signal from the indoor air thermostat; the controller
thereafter selectively operating the first blower, the first pump
and the second pump upon expiration of the timer.
10. The heat pump system of claim 5, wherein the first blower may
be operated at a plurality of speeds to provide a plurality of
forced air heating or cooling outputs.
11. The heat pump system of claim 10 wherein the controller
selectively operates the speed of the first blower in response to
the heating needs of the indoor air space.
12. The heat pump system of claim 10, the heat pump system further
including: an indoor air thermostat; the controller including an
internal timer, the controller starting the timer and activating
the primary compressor, the first blower and the second blower upon
receipt of a signal from the indoor air thermostat; the controller
thereafter increasing the speed of the first blower upon expiration
of the timer.
13. The heat pump system of claim 1, the heat pump system further
including: a controller; an indoor air thermostat: a sensor for
measuring the temperature of outdoor ambient air; the first blower
including a plurality of speed settings to provide a plurality of
forced air heating or cooling outputs; the controller activating
the primary compressor and the second blower upon receipt of a
signal from the indoor air thermostat; the controller also
activating the first blower at a predetermined setting based on the
temperature of outdoor ambient air upon receipt of a signal from
the indoor air thermostat.
14. The heat pump system of claim 1, the heat pump system further
including: a reversible valve connected to the conduit system, the
conduit system also circulating the refrigerant through the
reversible valve; the primary compressor and the fourth heat
exchanger being located on the compressor side of the reversible
valve and the first heat exchanger, second heat exchanger and the
third heat exchanger being located on the other side of the
reversible valve so that the flow of the refrigerant through the
first heat exchanger, the second heat exchanger and the third heat
exchanger may be reversed, thus allowing the heat pump system to
provide indoor heating when the refrigerant flows in one direction
and indoor cooling when the refrigerant flows in the other
direction; the fourth heat exchanger being located on the
compressor side of the reversible valve so that the water heating
system may provide heating for tap water when the heat pump system
is providing indoor heating or cooling.
15. The heat pump system of claim 2, the heat pump system further
including: a controller; the controller selectively operating the
primary compressor and the booster compressor in response to the
heating needs of the indoor air space.
16. The heat pump system of claim 2, the heat pump system further
including: a controller; an indoor air thermostat; the controller
including an internal timer, the controller starting the timer and
activating the primary compressor, the first blower and the second
blower upon receipt of a signal from the indoor air thermostat; the
controller thereafter activating the booster compressor upon
expiration of the timer.
17. The heat pump system of claim 3, the booster compressor having
a single output setting and the primary compressor having two
settings, a low output setting and a high output setting; the
primary compressor and the booster compressor operating in one of
three compressor output modes, a first output mode with the primary
compressor on low output and the booster compressor off, a second
output mode with the primary compressor on high output and the
booster compressor off, and a third output mode with the primary
compressor on high output and the booster compressor on.
18. The heat pump system of claim 17, the heat pump system further
including: a controller; an indoor air thermostat: the controller
activating the compressors in one of the three compressor output
modes upon receipt of a signal from the indoor air thermostat.
19. The heat pump system of claim 18, the heat pump system further
including; a sensor for measuring the temperature of outdoor
ambient air; the compressor output mode upon activation being
determined by the controller based on the temperature of the
outdoor ambient air.
20. The heat pump system of claim 18, the controller activating the
compressors in the first output mode when the temperature of the
outdoor ambient air is above a high predetermined temperature set
point, in the second output mode when the temperature of the
outdoor ambient air is below the high predetermined temperature set
point but above a low predetermined temperature set point and in
the third output mode when the temperature of the outdoor ambient
air is below the low predetermined temperature set point.
21. The heat pump system of claim 18, the controller including an
internal timer, the controller starting the timer upon receipt of a
signal from the indoor air thermostat and, upon expiration of the
timer, changing the compressors from the first output mode to the
second output mode or from the second output mode to the third
output mode.
22. The heat pump system of claim 18 having a high pressure side
and a low pressure side, the heat pump system further including: a
first sensor for measuring a parameter commensurate with the
pressure of the refrigerant on the high pressure side of the heat
pump system; a second sensor for measuring a parameter commensurate
with the pressure of the refrigerant on the low pressure side of
the heat pump system; the controller receiving a first input from
the first sensor and determining an actual or approximate pressure
of the refrigerant on the high pressure side of the heat pump
system; the controller receiving a second input from the second
sensor and determining an actual or approximate pressure of the
refrigerant on the low pressure side of the heat pump system; the
controller calculating a ratio of the pressure of the refrigerant
on the high pressure side of the heat pump system to the pressure
of the refrigerant on the low pressure side of the heat pump
system; the controller changing the compressors from the first
output mode to the second output mode or from the second output
mode to the third output mode when the ratio exceeds a certain
predetermined limit.
23. The heat pump system of claim 22 wherein the primary compressor
has an outlet and the first sensor is a pressure transducer that
measures pressure of the refrigerant on the high pressure side of
the heat pump system at the outlet of the primary compressor.
24. The heat pump system of claim 22 wherein the second sensor is a
temperature monitor that measures the temperature of the
refrigerant at the second heat exchanger.
25. The heat pump system of claim 18 having a high pressure side
and a low pressure side, the heat pump system further including: a
first sensor for measuring a parameter commensurate with the
pressure or temperature of the refrigerant on the high pressure
side of the heat pump system; the controller receiving a first
input from the first sensor and determining an actual or
approximate pressure or temperature of the refrigerant on the high
pressure side of the heat pump system; the controller changing the
compressors from the second output mode to the first output mode or
from the third output mode to the second output mode when the
pressure or temperature of the refrigerant on the high pressure
side of the heat pump system exceeds a certain predetermined
limit.
26. The heat pump system of claim 18 having a high pressure side
and a low pressure side, the heat pump system further including: a
first sensor for measuring the temperature or pressure of the
refrigerant on the high pressure side of the system; the controller
receiving a first input from the first sensor and determining an
actual or approximate pressure or temperature of the refrigerant on
the high pressure side of the heat pump system; the controller
deactivating the compressors when the pressure or temperature of
the refrigerant on the high pressure side of the heat pump system
exceeds a certain predetermined limit.
27. The heat pump system of claim 18 having a high pressure side
and a low pressure side, the system further including: a first pump
to circulate a fluid in heat exchange relationship with the third
heat exchanger; a first sensor for measuring a parameter
commensurate with the pressure or temperature of the refrigerant on
the high pressure side of the heat pump system; the controller
receiving a first input from the first sensor and determining an
actual or approximate pressure or temperature of the refrigerant on
the high pressure side of the heat pump system; the controller
activating the first pump when the pressure or temperature of the
refrigerant on the high pressure side of the heat pump system
exceeds a certain predetermined limit.
28. The heat pump system of claim 18 having a high pressure side
and a low pressure side, the heat pump system further including: a
pump to circulate a fluid in heat exchange relationship with the
fourth heat exchanger; a first sensor for measuring a parameter
commensurate with the pressure or temperature of the refrigerant on
the high pressure side of the heat pump system; the controller
receiving a first input from the first sensor and determining an
actual or approximate pressure or temperature of the refrigerant on
the high pressure side of the heat pump system; the controller
activating the pump when the pressure or temperature of the
refrigerant on the high pressure side of the heat pump system
exceeds a certain predetermined limit.
29. The heat pump system of claim 5 having a high pressure side and
a low pressure side, the heat pump system further including: a
first sensor for measuring a parameter commensurate with the
pressure or temperature of the refrigerant on the high pressure
side of the heat pump system; the controller receiving a first
input from the first sensor and determining an actual or
approximate pressure or temperature of the refrigerant on the high
pressure side of the heat pump system; the controller activating
the first pump when the pressure or temperature of the refrigerant
on the high pressure side of the heat pump system exceeds a certain
predetermined limit.
30. The heat pump system of claim 5 having a high pressure side and
a low pressure side, the heat pump system further including: a
first sensor for measuring a parameter commensurate with the
pressure or temperature of the refrigerant on the high pressure
side of the heat pump system; the controller receiving a first
input from the first sensor and determining an actual or
approximate pressure or temperature of the refrigerant on the high
pressure side of the heat pump system; the controller activating
the second pump when the pressure or temperature of the refrigerant
on the high pressure side of the heat pump system exceeds a certain
predetermined limit.
31. The heat pump system of claim 1, the heat pump system further
including: a controller; a receiver, the receiver being in
communication with a utility provider to receive a deactivation
signal indicating that the heat pump system must be deactivated,
the receiver further being in communication with the controller to
send a shut down signal to the controller; the controller
deactivating the heat pump system upon receipt of the shut down
signal from the receiver.
32. The heat pump system of claim 2, the heat pump system further
including: a controller; a receiver, the receiver being in
communication with a utility provider to receive a deactivation
signal indicating that the heat pump system must be deactivated,
the receiver further being in communication with the controller to
send a shut down signal to the controller; the controller
deactivating the heat pump system upon receipt of the shut down
signal from the receiver.
33. The heat pump system of claim 5, the heat pump system further
including: a receiver, the receiver being in communication with a
utility provider to receive a deactivation signal indicating that
the heat pump system must be deactivated, the receiver further
being in communication with the controller to send a shut down
signal to the controller; the controller deactivating the heat pump
system upon receipt of the shut down signal from the receiver.
34. The heat pump system of claim 14, the heat pump system further
including: a controller; a receiver, the receiver being in
communication with a utility provider to receive a deactivation
signal indicating that the heat pump system must be deactivated,
the receiver further being in communication with the controller to
send a shut down signal to the controller; the controller
deactivating the heat pump system upon receipt of the shut down
signal from the receiver.
35. The heat pump system of claim 18, the heat pump system further
including: a receiver, the receiver being in communication with a
utility provider to receive a deactivation signal indicating that
the heat pump system must be deactivated, the receiver further
being in communication with the controller to send a shut down
signal to the controller; the controller deactivating the heat pump
system upon receipt of the shut down signal from the receiver.
36. A heat pump system including: a primary compressor; a booster
compressor; a first heat exchanger for heating and/or cooling an
indoor space; a second heat exchanger for collecting energy from or
dissipating energy to an outdoor space; a third heat exchanger; a
water heating system in heat exchange relationship with the third
heat exchanger to provide heating for tap water; a conduit system
connecting the primary compressor, the booster compressor, the
first heat exchanger, the second heat exchanger and the third heat
exchanger, the conduit system circulating a refrigerant through the
primary compressor, the booster compressor, the first heat
exchanger, the second heat exchanger and the third heat
exchanger.
37. The heat pump system of claim 36, the heat pump system further
including: a controller; the water heating system including a pump
to circulate a fluid in heat exchange relationship with the third
heat exchanger; the controller operating the pump to provide
heating for tap water but deactivating the pump when the heat pump
system cannot provide sufficient heating or cooling for the indoor
space.
38. The heat pump system of claim 36, the heat pump system further
including: a reversible valve connected to the conduit system, the
conduit system also circulating the refrigerant through the
reversible valve; the primary compressor, the booster compressor
and the third heat exchanger being located on the compressor side
of the reversible valve and the first heat exchanger and the second
heat exchanger being located on the other side of the reversible
valve so that the flow of the refrigerant through the first heat
exchanger and the second heat exchanger may be reversed, thus
allowing the heat pump system to provide indoor heating when the
refrigerant flows in one direction and indoor cooling when the
refrigerant flows in the other direction; the third heat exchanger
being located on the compressor side of the reversible valve so
that the water heating system may provide heating for tap water
when the heat pump system is providing indoor heating or
cooling.
39. The heat pump system of claim 36, the heat pump system further
including: a pump to circulate a fluid in heat exchange
relationship with the third heat exchanger; a first sensor for
measuring a parameter commensurate with the pressure or temperature
of the refrigerant; the controller receiving a first input from the
first sensor and determining an actual or approximate pressure or
temperature of the refrigerant; the controller activating the pump
when the pressure or temperature of the refrigerant exceeds a
certain predetermined limit.
40. The heat pump system of claim 36, the booster compressor having
a single output setting and the primary compressor having two
settings, a low output setting and a high output setting; the
primary compressor and the booster compressor operating in one of
three compressor output modes, a first output mode with the primary
compressor on low output and the booster compressor off, a second
output mode with the primary compressor on high output and the
booster compressor off, and a third output mode with the primary
compressor on high output and the booster compressor on.
41. The heat pump system of claim 40, the heat pump system further
including: a controller; an indoor air thermostat: the controller
activating the compressors in one of the three compressor output
modes upon receipt of a signal from the indoor air thermostat.
42. The heat pump system of claim 41, the heat pump system further
including: a first sensor for measuring a parameter commensurate
with the pressure or temperature of the refrigerant; the controller
receiving a first input from the first sensor and determining an
actual or approximate pressure or temperature of the refrigerant; a
pump to circulate a fluid in heat exchange relationship with the
third heat exchanger; the controller activating the pump when the
pressure or temperature of the refrigerant exceeds a certain
predetermined limit.
43. The heat pump system of claim 36, the heat pump system further
including: a controller; a receiver, the receiver being in
communication with a utility provider to receive a deactivation
signal indicating that the heat pump system must be deactivated,
the receiver further being in communication with the controller to
send a shut down signal to the controller; the controller
deactivating the heat pump system upon receipt of the shut down
signal from the receiver.
44. A heat pump system including: a compressor; a first heat
exchanger for heating and/or cooling an indoor space; a second heat
exchanger for collecting energy from or dissipating energy to an
outdoor space; a third heat exchanger; a refrigerant conduit system
connecting the compressor, the first heat exchanger, the second
heat exchanger and the third heat exchanger, the refrigerant
conduit system circulating a refrigerant through the compressor,
the first heat exchanger, the second heat exchanger and the third
heat exchanger; a water heating system including a water heater
with a tap water inlet, a tap water outlet and a heating element;
the water heater functioning to hold tap water and heat tap water
with the heating element; the heating element being controlled by a
water heater thermostat; the water heating system further including
a heating loop and a pump, the pump circulating a fluid in the
heating loop in heat exchange relationship with the third heat
exchanger to deliver heat from the third heat exchanger to the
water heater to provide an alternative heating source for the tap
water in the water heater; an indoor thermostat; a controller
including a timer; the controller activating the compressor upon
receipt of a signal from the indoor thermostat; the controller
assuming control of the heating element of the water heater upon
receipt of a signal from the indoor thermostat to prevent operation
of the heating element and returning control of the heating element
to the water heater thermostat upon expiration of the timer.
45. The heat pump system of claim 44 further including a second
compressor.
46. A method of operating a heat pump system having a compressor, a
first heat exchanger, a second heat exchanger, a third heat
exchanger and a water heater, including the steps of: a) operating
the compressor to circulate a refrigerant in a refrigerant conduit
system connecting the compressor, the first heat exchanger, the
second heat exchanger and the third heat exchanger in response to a
signal from an indoor thermostat; b) operating a pump in response
to the same signal from the indoor thermostat to circulate a fluid
in heat exchange relationship with the third heat exchanger to
provide heat to the water heater for heating tap water, the water
heater also having a conventional water heater heating element and
a water heater thermostat to heat tap water when the pump is not
operating; c) deactivating the water heater heating element for a
predetermined time in response to the same signal from the indoor
thermostat so that the heat pump system may provide heat to the
water heater to heat tap water without intervention of the water
heater heating element; d) activating the water heater heating
element after the predetermined time so that the conventional
heating element may provide heat to the water heater if called for
by the water heater thermostat.
47. A method of operating a heat pump system having a compressor, a
first heat exchanger, a second heat exchanger, a third heat
exchanger and a water heater, including the steps of: a) operating
the compressor to circulate a refrigerant in a refrigerant conduit
system connecting the compressor, the first heat exchanger, the
second heat exchanger and the third heat exchanger; b) operating a
pump to circulate a fluid in heat exchange relationship with the
third heat exchanger to provide heat to the water heater for
heating tap water, the water heater also having a conventional
water heater heating element and a water heater thermostat to heat
tap water when the pump is not operating; c) deactivating the
compressor; d) deactivating the pump; e) deactivating the water
heater heating element for a predetermined time upon deactivation
of the compressor and pump to prevent the water heater heating
element from heating the tap water in the water heater during the
predetermined time when the compressor may be reactivated; f)
activating the water heater heating element after the predetermined
time so that the conventional heating element may provide heat to
the water heater if called for by the water heater thermostat.
48. A heat pump system including: a compressor; a first heat
exchanger; a second heat exchanger; a third heat exchanger; a
refrigerant conduit system connecting the compressor, the first
heat exchanger, the second heat exchanger and the third heat
exchanger, the refrigerant conduit system circulating a refrigerant
through the compressor, the first heat exchanger, the second heat
exchanger and the third heat exchanger; a first blower to direct
indoor air into heat exchange relationship with the first heat
exchanger to provide forced air heating or cooling for an indoor
air space; a second blower to direct outdoor air into heat exchange
relationship with the second heat exchanger to provide energy to
the system for heating or remove energy from the system for
cooling; a radiant heating system in heat exchange relationship
with the third heat exchanger to provide radiant heating for an
indoor space; the radiant heating system including a buffer tank, a
first pump and a first loop, the first pump circulating a fluid in
heat exchange relationship with the third heat exchanger to provide
heat for the buffer tank; the radiant heating system further
including a radiant heating loop pump and a radiant heating loop,
the radiant heating loop pump circulating a fluid from the buffer
tank to the radiant heating loop to provide heating for an indoor
space; the radiant heating system further including a radiant
heating thermostat and a buffer tank temperature sensor; a
controller with a timer, the timer being started upon a call for
heat from the radiant heating thermostat; the controller operating
the radiant heating loop pump upon receipt of a call for heating
from the radiant heating thermostat; the controller thereafter
operating the first pump to provide heat to the buffer tank after
expiration of the timer if the compressor is operating and if the
buffer tank temperature sensor is below a predetermined temperature
set point.
49. A method of operating a heat pump system having a compressor, a
first heat exchanger, a second heat exchanger, a third heat
exchanger, a radiant heating loop and a buffer tank, including the
steps of: a) monitoring a radiant heating thermostat; b) upon
receipt of a call for heat from the radiant heating thermostat,
starting a timer and activating a radiant heating loop pump to
provide heat to the radiant heating loop from the buffer tank; c)
upon expiration of the timer, monitoring a buffer tank temperature
sensor; d) if the buffer tank temperature sensor is below a
predetermined temperature set point after expiration of the timer
and the compressor is operating, activating a first pump to
circulate a fluid in heat exchange relationship with the third heat
exchanger to provide heat to the buffer tank; e) if the buffer tank
temperature sensor is below a predetermined temperature set point
after expiration of the timer and the compressor is not operating,
activating the compressor and the first pump to circulate a fluid
in heat exchange relationship with the third heat exchanger to
provide heat to the buffer tank.
50. A heat pump system including: a primary compressor; a booster
compressor; a first heat exchanger for heating and/or cooling an
indoor space; a second heat exchanger for collecting energy from or
dissipating energy to an outdoor space; a conduit system connecting
the primary compressor, the booster compressor, the first heat
exchanger and the second heat exchanger, the conduit system
circulating a refrigerant through the primary compressor, the
booster compressor, the first heat exchanger and the second heat
exchanger; the booster compressor having a single output setting
and the primary compressor having two settings, a low output
setting and a high output setting; the primary compressor and the
booster compressor operating in one of three compressor output
modes, a first output mode with the primary compressor on low
output and the booster compressor off, a second output mode with
the primary compressor on high output and the booster compressor
off, and a third output mode with the primary compressor on high
output and the booster compressor on. a first controller; a second
controller; the first controller establishing a request code for
one of the three compressor output modes based on a first system
parameter and sending the request code to the second controller;
the second controller evaluating the request code received from the
first controller and potentially changing the actual compressor
output mode based on a second system parameter.
51. The heat pump system of claim 50 wherein the first system
parameter is the outdoor ambient air temperature.
52. The heat pump system of claim 50, the heat pump system further
including: an indoor air thermostat; the first controller including
an internal timer, the internal timer being started upon receipt by
the first controller of a signal from the indoor air thermostat;
the first system parameter being the expiration of the timer.
53. The heat pump system of claim 50 having a high pressure side
and a low pressure side, the second system parameter being the
ratio of the pressure of the refrigerant on the high pressure side
to the pressure of the refrigerant on the low pressure side of the
heat pump system.
54. The heat pump system of claim 51 having a high pressure side
and a low pressure side, the second system parameter being the
ratio of the pressure of the refrigerant on the high pressure side
to the pressure of the refrigerant on the low pressure side of the
heat pump system.
55. The heat pump system of claim 52 having a high pressure side
and a low pressure side, the second system parameter being the
ratio of the pressure of the refrigerant on the high pressure side
to the pressure of the refrigerant on the low pressure side of the
heat pump system.
56. The heat pump system of claim 50 wherein the second parameter
is the pressure of the refrigerant.
57. The heat pump system of claim 51 wherein the second parameter
is the pressure of the refrigerant.
58. The heat pump system of claim 52 wherein the second parameter
is the pressure of the refrigerant.
59. The heat pump system of claim 50 wherein the second parameter
is the temperature of the refrigerant.
60. The heat pump system of claim 51 wherein the second parameter
is the temperature of the refrigerant.
61. The heat pump system of claim 52 wherein the second parameter
is the temperature of the refrigerant.
62. The heat pump system of claim 50 wherein the second parameter
is the percentage increase in the amperage of the primary
compressor over a predetermined period of time.
63. The heat pump system of claim 51 wherein the second parameter
is the percentage increase in the amperage of the primary
compressor over a predetermined period of time.
64. The heat pump system of claim 52 wherein the second parameter
is the percentage increase in the amperage of the primary
compressor over a predetermined period of time.
65. The heat pump system of claim 50, the heat pump system further
including: a receiver, the receiver being in communication with a
utility provider to receive a deactivation signal indicating that
the heat pump system must be deactivated, the receiver further
being in communication with the controller to send a shut down
signal to the controller; the controller deactivating the heat pump
system upon receipt of the shut down signal from the receiver.
66. A heat pump system including: a primary compressor; a booster
compressor; a first heat exchanger; a second heat exchanger; a
conduit system connecting the primary compressor, the booster
compressor, the first heat exchanger and the second heat exchanger,
the conduit system circulating a refrigerant through the primary
compressor, the booster compressor, the first heat exchanger and
the second heat exchanger; the booster compressor having a single
output setting and the primary compressor having two settings, a
low output setting and a high output setting; the primary
compressor and the booster compressor operating in one of three
compressor output modes, a first output mode with the primary
compressor on low output and the booster compressor off, a second
output mode with the primary compressor on high output and the
booster compressor off, and a third output mode with the primary
compressor on high output and the booster compressor on. a
controller; an indoor air thermostat: the controller activating the
compressors in one of the three compressor output modes upon
receipt of a signal from the indoor air thermostat. the controller
including an internal timer, the controller starting the timer upon
receipt of a signal from the indoor air thermostat and, upon
expiration of the timer, changing the compressors from the first
output mode to the second output mode or from the second output
mode to the third output mode.
67. A heat pump system including: a primary compressor; a booster
compressor; a first heat exchanger; a second heat exchanger; a
conduit system connecting the primary compressor, the booster
compressor, the first heat exchanger and the second heat exchanger,
the conduit system circulating a refrigerant through the primary
compressor, the booster compressor, the first heat exchanger and
the second heat exchanger; the booster compressor having a single
output setting and the primary compressor having two settings, a
low output setting and a high output setting; the primary
compressor and the booster compressor operating in one of three
compressor output modes, a first output mode with the primary
compressor on low output and the booster compressor off, a second
output mode with the primary compressor on high output and the
booster compressor off, and a third output mode with the primary
compressor on high output and the booster compressor on. a
controller; an indoor air thermostat: the controller activating the
compressors in one of the three compressor output modes upon
receipt of a signal from the indoor air thermostat. the heat pump
system having a high pressure side and a low pressure side; a first
sensor for measuring a parameter commensurate with the pressure of
the refrigerant on the high pressure side of the heat pump system;
a second sensor for measuring a parameter commensurate with the
pressure of the refrigerant on the low pressure side of the heat
pump system; the controller receiving a first input from the first
sensor and determining an actual or approximate pressure of the
refrigerant on the high pressure side of the heat pump system; the
controller receiving a second input from the second sensor and
determining an actual or approximate pressure of the refrigerant on
the low pressure side of the heat pump system; the controller
calculating a ratio of the pressure of the refrigerant on the high
pressure side of the heat pump system to the pressure on the low
pressure side of the heat pump system; the controller changing the
compressors from the first output mode to the second output mode or
from the second output mode to the third output mode when the ratio
exceeds a certain predetermined limit.
68. The heat pump system of claim 67 wherein the primary compressor
has an outlet and the first sensor is a pressure transducer that
measures pressure of the refrigerant on the high pressure side of
the heat pump system at the outlet of the primary compressor.
69. The heat pump system of claim 67 wherein the second sensor is a
temperature monitor that measures the temperature of the
refrigerant at the second heat exchanger.
70. A heat pump system including: a primary compressor; a booster
compressor; a first heat exchanger; a second heat exchanger; a
third heat exchanger; a conduit system connecting the primary
compressor, the booster compressor, the first heat exchanger, the
second heat exchanger and the third heat exchanger, the conduit
system circulating a refrigerant through the primary compressor,
the first heat exchanger, the second heat exchanger and the third
heat exchanger; a first blower to direct indoor air into heat
exchange relationship with the first heat exchanger to provide
forced air heating or cooling for an indoor air space; a second
blower to direct outdoor air into heat exchange relationship with
the second heat exchanger to provide energy to the system for
heating or remove energy from the system for cooling; a first pump
to circulate a fluid in heat exchange relationship with the third
heat exchanger; the booster compressor having a single output
setting and the primary compressor having two settings, a low
output setting and a high output setting; the primary compressor
and the booster compressor operating in one of three compressor
output modes, a first output mode with the primary compressor on
low output and the booster compressor off, a second output mode
with the primary compressor on high output and the booster
compressor off, and a third output mode with the primary compressor
on high output and the booster compressor on. a controller; an
indoor air thermostat: the controller activating the compressors in
one of the three compressor output modes upon receipt of a signal
from the indoor air thermostat. a first sensor for measuring a
parameter commensurate with the pressure or temperature of the
refrigerant; the controller receiving a first input from the first
sensor and determining an actual or approximate pressure or
temperature of the refrigerant; the controller activating the first
pump when the pressure or temperature of the refrigerant exceeds a
certain predetermined limit.
71. A heat pump system including: a compressor; a first heat
exchanger for heating and/or cooling an indoor space; a second heat
exchanger for collecting energy from or dissipating energy to an
outdoor space; a third heat exchanger; a water heating system in
heat exchange relationship with the third heat exchanger to provide
heating for tap water; a conduit system connecting the compressor,
the first heat exchanger, the second heat exchanger and the third
heat exchanger, the conduit system circulating a refrigerant
through the compressor, the first heat exchanger, the second heat
exchanger and the third heat exchanger; a controller; the water
heating system including a pump to circulate a fluid in heat
exchange relationship with the third heat exchanger; the controller
operating the pump to provide heating for tap water but
deactivating the pump when the heat pump system cannot provide
sufficient heating or cooling for the indoor space.
72. A heat pump system including: a compressor; a first heat
exchanger for heating and/or cooling an indoor space; a second heat
exchanger for collecting energy from or dissipating energy to an
outdoor space; a third heat exchanger; a water heating system in
heat exchange relationship with the third heat exchanger to provide
heating for tap water; a conduit system connecting the compressor,
the first heat exchanger, the second heat exchanger and the third
heat exchanger, the conduit system circulating a refrigerant
through the compressor, the first heat exchanger, the second heat
exchanger and the third heat exchanger; a reversible valve
connected to the conduit system, the conduit system also
circulating the refrigerant through the reversible valve; the
compressor and the third heat exchanger being located on the
compressor side of the reversible valve and the first heat
exchanger and the second heat exchanger being located on the other
side of the reversible valve so that the flow of the refrigerant
through the first heat exchanger and the second heat exchanger may
be reversed, thus allowing the heat pump system to provide indoor
heating when the refrigerant flows in one direction and indoor
cooling when the refrigerant flows in the other direction; the
third heat exchanger being located on the compressor side of the
reversible valve so that the water heating system may provide
heating for tap water when the heat pump system is providing indoor
heating or cooling.
73. A heat pump system including: a compressor; a first heat
exchanger for heating and/or cooling an indoor space; a second heat
exchanger for collecting energy from or dissipating energy to an
outdoor space; a third heat exchanger; a water heating system in
heat exchange relationship with the third heat exchanger to provide
heating for tap water; a conduit system connecting the compressor,
the first heat exchanger, the second heat exchanger and the third
heat exchanger, the conduit system circulating a refrigerant
through the compressor, the first heat exchanger, the second heat
exchanger and the third heat exchanger; a pump to circulate a fluid
in heat exchange relationship with the third heat exchanger; a
first sensor for measuring a parameter commensurate with the
pressure or temperature of the refrigerant; the controller
receiving a first input from the first sensor and determining an
actual or approximate pressure or temperature of the refrigerant;
the controller activating the pump when the pressure or temperature
of the refrigerant exceeds a certain predetermined limit.
74. The heat pump system of claim 71, the heat pump system further
including: a controller; a receiver, the receiver being in
communication with a utility provider to receive a deactivation
signal indicating that the heat pump system must be deactivated,
the receiver further being in communication with the controller to
send a shut down signal to the controller; the controller
deactivating the heat pump system upon receipt of the shut down
signal from the receiver.
75. The heat pump system of claim 72, the heat pump system further
including: a controller; a receiver, the receiver being in
communication with a utility provider to receive a deactivation
signal indicating that the heat pump system must be deactivated,
the receiver further being in communication with the controller to
send a shut down signal to the controller; the controller
deactivating the heat pump system upon receipt of the shut down
signal from the receiver.
76. The heat pump system of claim 73, the heat pump system further
including: a controller; a receiver, the receiver being in
communication with a utility provider to receive a deactivation
signal indicating that the heat pump system must be deactivated,
the receiver further being in communication with the controller to
send a shut down signal to the controller; the controller
deactivating the heat pump system upon receipt of the shut down
signal from the receiver.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a Continuation-in-Part of Application
Serial No. US 2005/0252226 A1, entitled "Heating/Cooling System"
and filed May 11, 2005, the contents of which are incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to heating and
cooling systems and more specifically to a heating and cooling
system with multiple compressors, multiple heat outputs and the
control system for managing the system.
BACKGROUND OF THE INVENTION
[0003] Heat pump systems have found widespread application for
heating and cooling homes and businesses. Because heat pump systems
utilize the same primary components for both heating and cooling,
they eliminate the need for separate heating and cooling systems
and are therefore economical to install and use. Heat pump systems
are also highly efficient, resulting in decreased energy costs to
the consumer. As a result, the demand for heat pump systems in
residential and business applications has continued to grow in
recent years.
[0004] The use of conventional heat pump systems in colder
climates, however, presents significant challenges. In heating
mode, a heat pump system draws heat energy from the outdoor air to
heat an indoor space. Even at low ambient temperatures, heat may be
drawn from the outdoor environment by evaporating refrigerant in an
outdoor evaporator. The evaporated refrigerant is then compressed
by one or more compressors and then cycled to an indoor condenser
where the energy of the compressed refrigerant is released to the
indoor space. The refrigerant is then cycled back to the outdoor
evaporator to repeat the cycle.
[0005] At very low temperatures, however, it becomes increasingly
difficult to draw heat from the outdoor environment. In addition,
at very low temperatures, the outdoor heat exchange coil is very
susceptible to frost build up, which limits air flow across the
coil. As a result, the performance and efficiency of heat pump
systems decreases drastically at very low ambient temperatures when
heating capacity is most needed. To address this issue, increased
compressor capacity is required for heat pump systems installed in
colder climates. Single compressor systems have been utilized that
can provide heating at low to moderate ambient temperatures, but
such systems typically demonstrate decreased efficiency and
performance at higher temperatures. Such systems must cycle on and
off frequently at higher ambient temperatures, resulting in a
reduced lifespan for the compressor and decreased system
efficiency. Variable speed compressors have been used to address
this problem, but these types of compressors are expensive and lead
to increased installation costs for the system.
[0006] Multiple compressor systems have been proposed to adapt the
heat pump concept for use in colder climates. These systems utilize
a primary compressor for heating and cooling in moderate
temperatures, and also include a booster compressor to provide
increased capacity at very low temperatures. An economizer, which
utilizes a diverted portion of the refrigerant flow to subcool the
refrigerant flowing to the evaporator, may also be used to provide
increased heating capacity at very cold temperatures. Systems
utilizing multiple compressors and an economizer are disclosed, for
example, in U.S. Pat. Nos. 5,927,088, 6,276,148 and 6,931,871
issued to Shaw. Although the systems disclosed in these patents
address the need to provide increased heating capacity at very cold
temperatures, those of skill in the art have continued to seek
sophisticated methods that effectively control the multiple
compressors to maximize system efficiency and utilize the full
output potential of the compressors.
[0007] In particular, prior art systems have controlled multiple
compressors based on limited system inputs. For example, the '148
and '871 patents issued to Shaw disclose dual compressor systems
that select compressor output in response to decreases and/or
increases in outdoor ambient temperature. The '871 patent issued to
Shaw discloses a system that selects compressor output in response
to a multi-step indoor thermostat and the system low side pressure,
which pressure is commensurate with outdoor ambient air temperature
during all heating cycle modes of operation. These control
methodologies, however, may lead to frequent calls for changes in
compressor output, which will cause one or both of the compressors
to cycle on and off. Although important to prevent unsafe and
inefficient compressor operation, a system control that more
effectively manages when compressors are turned on and off is
desirable. Such a system may lead to increased compressor run times
in a consistent output condition, which increases the life of the
compressors and overall system efficiency.
[0008] Prior art systems have disclosed the use of multiple
compressors to provide heat for an indoor forced air heat
exchanger. With multiple compressors, however, additional heating
capacity is present that may also be utilized for an additional
indoor heating system such as a hydronic floor system. The heat
pump system may also provide energy for a tap water heater. With
these additional heating components integrated into the heat pump
system, the potential output of the compressors may be more fully
realized, providing further justification for the cost of the
system. Further, if properly configured and controlled, these
additional heating components may be used to absorb excess energy
produced by the compressors to address and limit high pressure and
temperature conditions. Also, with multiple heating components
receiving energy input from the compressors, compressor run time
can be increased. With the compressors cycling on and off less
frequently, the life span and efficiency of the compressors is
increased.
[0009] Despite the increased capacity provided by multiple
compressors, heat pump systems installed in very cold climates may
require some form of back up heating to address the very coldest
conditions. Prior art systems, however, have not effectively
integrated control of the back up heating system with the control
of the heat pump system. As a result, the back up heating system,
which performs at lower efficiency, is over utilized as compared to
the heat pump system, leading to increased energy costs. If the two
systems are effectively integrated and controlled, the higher
efficiency of the heat pump system may be more fully utilized even
during the coldest months of the year.
[0010] Finally, those of skill in the art have sought a heat pump
system that effectively integrates utility Load Management Control.
Load Management Control, or LMC, allows a utility company to
remotely and temporarily shut down certain users' heating and
cooling systems at times when the utility is experiencing peak
loads. Because this capability is desirable for utility companies,
energy consumers that implement this feature may receive decreased
energy rates, tax incentives or other consideration. To implement
LMC, an auxiliary heating system with a different energy source,
such as a gas furnace, is typically required to provide heat when
the utility initiates a system shut down in cold weather
conditions. Control of this alternative heating source is
preferably integrated with control of the heat pump system so that
the system effectively and efficiently transitions to the
alternative heat source when a shut down command is received, and
also easily transitions back to the main heating system when the
shut down condition terminates.
[0011] Accordingly, an object of the present invention is to
provide a heat pump system for use in colder climates that is
economical to install and use.
[0012] An additional object of the present invention is to provide
a heat pump system with multiple compressors that effectively
controls the compressors to maximize system efficiency and utilize
the full output potential of the compressors.
[0013] A further object of the present invention is to provide a
heat pump system with multiple heat outputs including a forced air
heater, a hydronic floor heating system and/or a water heater.
[0014] Yet another object of the present invention is to provide a
heat pump control system that may easily and effectively divert
compressor energy to multiple heat outputs to fully utilize the
output of the compressors, address high pressure and temperature
conditions, increase compressor run times, decrease compressor
cycling and maximize the overall efficiency of the system.
[0015] Still another object of the present invention is to provide
a heat pump control system that effectively integrates a back up
heating system for use in the very coldest conditions.
[0016] A still further object of the present invention is to
provide a heat pump system that effectively integrates utility Load
Management Control.
[0017] Additionally, an object of the present invention is to
provide a heat pump system that may effectively defrost the outdoor
coil.
[0018] Finally, an object of the present invention is to provide a
heat pump system that provides energy for heating tap water when
the system is in use for either heating or cooling, and also
minimizes the use of the water heater element under all
conditions.
SUMMARY OF THE INVENTION
[0019] The preferred embodiment of the present invention provides
increased heating capacity through the use of a primary compressor,
a booster compressor and an economizer. The system effectively
utilizes this heating capacity with three heat exchangers that
provide 1) indoor air heating or cooling, 2) hydronic floor heating
and 3) tap water heating. In addition to providing additional
heating capabilities, the heat energy generated by the system may
be easily diverted between the indoor air heating system, the
hydronic floor heating system and the water heater to provide
maximum comfort and energy utilization, store energy for later use
and address fluctuations in the energy output of the system.
[0020] The system utilizes a novel control system that: 1) prevents
unsafe operating parameters; 2) ensures comfortable indoor heating
and cooling; 3) utilizes any excess energy present in the system,
or stores that energy for later use, by diverting the energy to the
hydronic floor heating system and/or the water heater and 4)
provides for long run times of the system at optimal conditions to
prevent unnecessary and intermittent start up of the
compressors.
[0021] The system further includes a backup heating source that is
effectively integrated and controlled by the system. Load
Management Control is also provided so that the system may be shut
down remotely by a utility company.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a schematic of the preferred embodiment of the
heating and cooling system of the present invention.
[0023] FIG. 2(a) is a schematic of the System Control of the
present invention.
[0024] FIG. 2(b) is a schematic showing the interaction of the Heat
Pump Manager with System Control of the present invention.
[0025] FIG. 3 is a chart showing the decision process employed by
System Control when it receives a call for heat from the indoor
thermostat when the outdoor ambient temperature is high.
[0026] FIG. 4 is a chart showing the decision process employed by
System Control when it receives a call for heat from the indoor
thermostat when the outdoor ambient temperature is medium.
[0027] FIG. 5 is a chart showing the decision process employed by
System Control when it receives a call for heat from the indoor
thermostat when the outdoor ambient temperature is low.
DETAILED DESCRIPTION
[0028] FIG. 1 is a schematic of one embodiment of the heating and
cooling system 10 of the present invention. The primary components
of the system include a primary compressor 12, a booster compressor
14, a first condenser 16, a second condenser 18, a third condenser
20, an economizer 22, an evaporator 24 and a 4-way valve 26.
[0029] The primary compressor 12 is preferably a scroll-type
two-speed compressor that may be operated at two discrete discharge
pressure settings. The booster compressor 14 is preferably a
single-speed compressor that may be operated at a single discharge
pressure setting. The two compressors may be operated in series or
the booster compressor 14 may be bypassed by opening booster
compressor bypass valve 28. A temperature sensor (HIT) monitors the
temperature and a pressure sensor (HI) monitors the pressure of the
refrigerant exiting the primary compressor 12.
[0030] In the preferred embodiment of the present invention, and
depending upon the heating and cooling demands on the system, the
system is operated in one of three compressor output modes. First,
the primary compressor 12 may be operated at low output. Second,
the primary compressor 12 may be operated at high output. Third,
both the booster compressor 14 and the primary compressor 12 may be
operated with the primary compressor operating at high output.
These compressor output modes and the system controls that
determine which mode to utilize at any given time will be described
in detail below.
[0031] Compressed refrigerant from the compressors is directed to
the third condenser 20 on the compressor side of system. In the
third condenser 20, the high-pressure condensed refrigerant
transfers heat to water that is circulated by a water heater pump
30 to a water heater 32. The water heater 32 utilizes the heat from
the third condenser 20 to heat tap water for home or business use.
The water heater 32 also includes a conventional heating element 34
that may also be used to heat the tap water. A temperature monitor
(WH-RT) 116 senses the temperature of the water returning to the
third condenser 20 from the water heater 32. Because the third
condenser 20 is located on the compressor side of the 4-way valve
26, the third condenser may provide heat for water heating
regardless of whether the system is in heating or cooling mode.
[0032] In heating mode, the refrigerant flows from the 4-way valve
26 to the first condenser 16, which provides heat for a hydronic
floor heating system 36. A buffer tank pump 38 circulates water
through the first condenser 16 and draws heat from the refrigerant
to heat the water stored in a buffer tank 40. A hydronic floor
heating system pump 42 circulates the heated water from the buffer
tank 40 to a hydronic loop 43 to heat the floor of an indoor space.
Additional hydronic circuits with independent pumps or zone valves
may also be provided to supply additional zones with hydronic
heating from the buffer tank. A temperature monitor (WIT) 114
senses the temperature of the water in the buffer tank 40. A
temperature monitor (W-ST) 115 monitors the temperature of the
water circulated through the first condenser 16.
[0033] In certain installation configurations where the hydronic
floor has sufficient capacity (minimum radiant floor size of at
least 35,000 Btu/hr, or approximately 1800 sq. ft.), the buffer
tank 40 may not be required. In these installations, the hydronic
floor system water may be circulated in direct heat exchange
relationship with the first condenser 16 to provide heat for the
hydronic floor system without the need for a buffer tank. In this
arrangement, the WIT 114 and W-ST 115 temperature monitors are
placed in the same hot water pipe.
[0034] After the first condenser, the refrigerant flows to a second
condenser 18, which provides air heating for an indoor space.
Although referred to herein as a "condenser," which is the function
it performs in heating mode, the second condenser 18 operates as an
evaporator in cooling mode. A blower 44 directs air over the second
condenser 18 and draws heat from the refrigerant. The blower 44 is
preferably a forced air ECM variable speed blower. A temperature
monitor (ST) 111 senses the temperature of the air being heated by
the second condenser 18.
[0035] After the second condenser 18, the refrigerant flows to a
receiver 50 and then to an economizer 22. After the economizer 22,
a portion of the refrigerant flow may be diverted through an
expansion valve 46 and back to the economizer 22 in heat exchange
relationship with original refrigerant flow. The diverted flow then
flows from the economizer 22 to a mixing chamber 48 on the
compression side of the system where the two phase refrigerant is
mixed with superheated vapor leaving the booster compressor 14
prior to entering the primary compressor 12.
[0036] The remainder of the refrigerant flows to the evaporator 24
where a fan 51 blows air over the evaporator 24 to draw heat into
the system. Although referred to herein as an "evaporator," which
is the function it performs in heating mode, the evaporator
operates as a condenser in cooling mode. A temperature monitor (OT)
110 senses the outdoor temperature at the outdoor evaporator. A
temperature monitor (ET) also senses the evaporating temperature of
the refrigerant at the evaporator.
[0037] After the evaporator 24, the refrigerant flows through the
4-way valve 26 and back to the compression side of the system to
repeat the cycle. An oil filtering and equalization system is also
provided on the compression side of the system. Refrigerant leaving
the compressors may have oil from the compressors entrained in the
refrigerant which will degrade system performance. The oil is
separated from the refrigerant by an oil separator 52 and oil
filter 54 and returned to the suction side of the primary
compressor 12 at point 56 to guarantee lubrication for the
compressor.
[0038] Oil may also tend to migrate from one compressor to the
other depending on the operating conditions of the system. To
address oil migration, an oil equalization valve 58 is provided
that is opened in certain conditions when the compressors are
turned off to allow the oil level between the compressors to
equalize. An accumulator 60 is also provided that regulates
refrigerant flow to the compressors and protects the compressors
from damage during startup.
[0039] An auxiliary 120 (FIG. 2(a)) or backup electric resistance
heating system is also provided that may be used when the primary
system components cannot provide adequate heating in extreme cold
conditions or to remove load from the compressors under any
operating conditions. If a remote utility Load Management Control
receiver is implemented with the present system, as described in
detail below, a heating system with a different energy source, such
as a gas furnace, may also be provided so that the system may
utilize this alternative energy heat source when shut down by the
Load Management Control receiver.
[0040] In cooling mode, only the primary compressor 12 is operated,
and it may be operated at either high or low capacity. At the 4-way
valve 26, the direction of flow is reversed so that the compressed
refrigerant flows in the opposite direction on the heat exchange
side of the system. Thus, the compressed refrigerant flows from the
4-way valve 26 to the evaporator 24 (now operating as a condenser)
where heat is released to the outdoors. The refrigerant then flows
to the second condenser 18 (now operating as an evaporator) and the
refrigerant draws heat from the indoor air space. In cooling mode,
the first condenser 16 is bypassed by opening valve 62 and closing
valve 64, and refrigerant flows from the second condenser 18 to the
4-way valve 26 and back to the compression side of the system to
repeat the cycle.
[0041] Defrost mode is similar to cooling mode, except that the
first condenser 16 is not bypassed. When the system is in heating
mode and the outdoor evaporator requires defrosting, the 4-way
valve 26 is reversed and compressed refrigerant is circulated to
the evaporator 24 to defrost the coil. The refrigerant then flows
to the second condenser 18, where the blower 44 is turned off, and
then to the first condenser 16. To direct the flow of the
refrigerant to the first condenser 16, valve 62 is closed and valve
64 is opened. A temperature monitor (FT) senses the temperature of
the refrigerant entering the first condenser 16. At the first
condenser 16, the refrigerant draws heat from the water circulating
to the hydronic floor heating buffer tank 40. The refrigerant then
flows through the 4-way valve 26 and back to the compression side
of the system to repeat the cycle. Thus, the heat from the first
condenser 16 is delivered to the evaporator 24 to defrost the coil.
When defrosting is completed, the system returns to heating
mode.
[0042] As described above, the heating and cooling system 10 of the
present invention includes temperature sensors throughout the
system. The system also includes sensors that can shut off
electrical power to one or both of the compressors under certain
conditions. A mechanical safety sensor (HP) 68 detects the pressure
of the refrigerant leaving the primary compressor 12 and will shut
off the compressors if the pressure exceeds a certain maximum.
Similarly, a mechanical disk thermostat (HT) 70 detects the
temperature of the refrigerant leaving the primary compressor 12
and will shut off the compressor if the temperature exceeds a
certain maximum. Additional pressure sensors are also located
throughout the system and continuously monitor the pressure at
various points in the system.
[0043] The preferred embodiment of the system includes an indoor
thermostat 112 (AIR-W, AIR-Y or AIR-G) that is a conventional,
4-wire, RWGY thermostat with a single-step setting for heat (AIR-W)
and a single-step setting for cooling (AIR-Y). If set to heating,
the indoor thermostat monitors the temperature of the indoor air
space and calls for heating (AIR-W) at a temperature set at the
thermostat. If set to cooling, the indoor thermostat 112 monitors
the temperature of the indoor air space and calls for cooling
(AIR-Y) at a temperature set at the thermostat.
[0044] The hydronic floor heating system 36 includes a thermostat
(LOOP-W) 113 (FIG. 2(a)). This thermostat monitors the temperature
of the hydronic floor heating system 36 and activates the pump 42
when the hydronic floor system requires heat. Upon request from the
thermostat (LOOP-W) 113, the pump 42 circulates heated water from
the buffer tank 40 to the hydronic floor system 36.
[0045] FIG. 2(a) is a schematic of the control system of the
present invention. The primary inputs to the System Control 100 are
received from an outdoor temperature monitor (OT) 110, an air
supply temperature monitor (ST) 111, an indoor thermostat 112,
LOOP-W 113, a temperature monitor for the water in the buffer tank
(WIT) 114, a temperature monitor for the water in first condenser
(W-ST) 115, a temperature monitor for the water in the third
condenser (WH-RT) 116, the utility load management 117, the standby
heat 121 and the Heat Pump Manager (HPM) 102 (collectively, "the
inputs"). The primary outputs from the system control 100 may be
sent to the ECM Blower 44, the buffer tank pump 38, the water
heater pump 30, the HPM 102, the standby heat 121, the auxiliary
electric 120 and the water heater 32 (collectively, "the
outputs").
[0046] The System Control 100 receives inputs from the monitoring
devices throughout the system, processes these signals, and makes a
"request" to the Heat Pump Manager (HPM) 102 for an operational
compressor sequence. As will be described in detail below, the
System Control 100 is designed to maximize system efficiency.
Through use of decision tables, the System Control 100 processes
the inputs to control the outputs so that excess energy may be
transferred within the system for maximum performance.
[0047] FIG. 2(b) is a schematic showing the interaction of the Heat
Pump Manager 102 with System Control 100 of the present invention.
This schematic shows the interconnectivity between the System
Control 100 and the HPM 102 and the various components of the
present invention. The various components include the System
Control 100, the Heat Pump Manager (HPM) 102, the standby heat 121,
the utility load management 117, the outdoor unit 25, the water
heater 32, the relays 125, the blower 44, the limits 127 and the
compressors 126. The outdoor unit 25 includes evaporator 24, fan 51
and temperature monitor ET (as shown in FIG. 1). Relays 125 include
the buffer tank pump 38, the water heater pump 30, the auxiliary
heat 120 and the water heater 32.
[0048] As shown in FIG. 2(b), the HPM 102 communicates with the
compressors 127, which includes the primary compressor 12 and the
booster compressor 14. Furthermore, the HPM 102 utilizes the Limits
127, which includes high pressure (HP) 68 and high temperature (HT)
70 within the system. The HPM 102 monitors the Limits 127 to ensure
safe operating conditions and system efficiency. FIG. 2(b) also
shows the HPM 102 interacting with the outdoor unit 25. When the
defrost mode is activated, the HPM 102 controls the outdoor unit
25, the compressors 126 and the limits 127 as will be further
described below.
[0049] In the preferred embodiment of the present invention, System
Control 100 and HPM 102 are separate computers or controllers.
However, the functions of System Control 100 and HPM 102 may be
integrated into a single computer or controller and remain within
the scope of the present invention.
[0050] The HPM 102 may override or modify the operating parameters
set by the System Control 100 based on additional calculations
performed by the HPM 102 and/or preset operating limits for certain
system components. The HPM 102 thus sets the "actual," or real
time, stage code for the system and prevents unsafe or less than
optimal operating conditions.
[0051] The system uses eight Stage Codes that correspond to certain
operating configurations for the compressors:
TABLE-US-00001 0 System is off 1 Heat - primary compressor on low 2
Heat - primary compressor on high 3 Heat - primary compressor on
high, booster compressor on 4 Add Load capacity 5 Cool - primary
compressor on low 6 Cool - primary compressor on high 7 System hold
- safety or performance interrupt
[0052] The system is activated when the indoor thermostat 112 calls
for heating (AIR-W) or cooling (AIR-Y), or when the buffer tank 40
requires heating. When the indoor thermometer calls for heating
(AIR-W), the System Control 100 determines a Request Stage Code and
indoor air blower 44 speed based on the outdoor temperature (OT).
In the figures, a symbol (e.g., "OT") together with a reference
number is used to designate the temperature monitor. However, when
the symbol alone is used, the symbol designates the temperature
readout on the corresponding temperature monitor. Thus, for
example, OT 110 designates the outdoor temperature monitor and "OT"
alone designates the temperature readout from the outdoor
temperature monitor.
[0053] If the outdoor temperature (OT) is high (>500), System
Control 100 requests Stage Code 1 (primary compressor 12 on low)
from the HPM 102 and sets the indoor air blower 44 speed to low. If
the outdoor temperature (OT) is medium (<55.degree. F. and
>20.degree. F.), System Control 100 requests Stage Code 2
(primary compressor 12 on high) and sets the indoor air blower 44
speed to medium. If the outdoor temperature (OT) is low
(<20.degree. F.), System Control 100 requests Stage Code 3
(primary compressor 12 on high and booster compressor 14 on) and
sets the indoor air blower 44 speed to high. System Control 100
then controls the blower 44, the buffer tank pump 38, the water
heater pump 30 and potentially the auxiliary heating elements
according to the decision tables shown in FIGS. 3-5.
[0054] Thus, based on the outdoor temperature, System Control 100
sets the indoor air blower speed and the output of the compressors,
which in turn determine the BTU delivery into the indoor air space.
Although the outdoor temperature determines the initial blower and
compressor settings, System Control 100 may then alter these
parameters, along with BTU delivery to the buffer tank 40 and the
water heater 32, to maximize indoor air comfort and system
efficiency. If the indoor air thermostat (AIR-W) is not satisfied
after a preset time, System Control 100 may increase the blower
speed and increase the Request Stage Code to the HPM 102 for the
compressors. If both the blower 44 and the compressors 126 are in
highest output mode and the indoor air thermostat 112 remains
unsatisfied, System Control 100 may add auxiliary heating to
satisfy the indoor air thermostat 112 call for heat.
[0055] To maximize system efficiency, System Control 100 monitors
the air supply temperature (ST) at the indoor blower 44. If ST is
either too low to heat the indoor air space or too high for
efficient compressor operation, System Control 100 may either
change the Request Stage Code for the compressors or activate or
deactivate the buffer tank pump 38 and/or the water heater pump
30.
[0056] For best system efficiency, System Control 100 attempts to
keep the buffer tank pump 38 and the water heater pump 30 running
to utilize any excess energy within the system. Also, by diverting
energy to the buffer tank 40 and the water heater 32 whenever
possible, compressor run time is increased, which decreases the
wear and tear on the compressors caused by frequent start ups.
Thus, whenever ST appears to be sufficient to satisfy the call for
heat, the buffer tank pump 38 and the water heater pump 30 are
activated or kept running. However, if ST goes low, the buffer tank
pump 38 and/or the water heater pump 30 may be deactivated so that
sufficient energy is available for heating the indoor air
space.
[0057] The decision steps utilized by System Control 100 after
receiving a call for heat from the indoor air thermostat 112
(AIR-W) are shown in FIGS. 3-5. Within these tables, "ST" is the
temperature of the air being heated by the second condenser 18 at
the indoor air blower 44. In the ST columns, L, M, H are low,
medium and high set points for the ST temperature, which are
preferably set at 92.degree. F., 96.degree. F. and 102.degree. F.
respectively. The "-" and "+" signs refer to the ST temperature
dropping below ("-") or rising above ("+") the associated set
point.
[0058] "Timer" is an internal timer in the System Control 100 that
measures the length of time since the indoor thermostat 112 has
called for heat, thus providing a measure of time since the indoor
thermostat 112 has remained unsatisfied. MU1 is a shorter timer,
preferably 15 minutes, and MU2 is a longer timer, preferably 45
minutes.
[0059] "W-ST" is the temperature of the water circulated to the
buffer tank 40 by the buffer tank pump 38. If this temperature
exceeds a certain set point, preferably 105.degree. F., the system
attempts to divert heat from the buffer tank 40.
[0060] "Blower" is the forced air ECM variable speed indoor air
blower 44. The air blower speed (L, M or H), which is set by System
Control 100, determines BTU delivery into the indoor air space
(BTU=1.08.times.CFM.times.temperature differential).
[0061] "Aux" is an auxiliary heating system 120 that may be
activated if heating requirements cannot be met by the system. The
auxiliary heating system 120 may be any type of alternative heating
component or system including an electrical resistance heater, a
gas furnace or other type of heating. Auxiliary heating may be
provided at low (EL1) or high (EL2) output.
[0062] "Tank pump" is the buffer tank pump 38. The buffer tank pump
38 is activated whenever possible to divert energy to the buffer
tank 40, and also as a control mechanism to address high
temperature and pressure conditions in the system.
[0063] "WH Pump" is the water heater pump 30. As explained below,
the water heater pump is nearly always set to "ON" whenever the
system is running so that heat may be provided to the water heater
32 for water heating. However, when additional heat is needed to
heat the indoor air space, or if the temperature water circulated
to the water heater 32 exceeds a certain temperature, preferably
135.degree. F., the water heater pump 30 may be deactivated.
[0064] "Stage Code" is the Stage Code requested by System Control
100, which may be modified by the HPM 102 as will be described in
detail below.
[0065] Within FIGS. 3-5, the "+" symbol means that the system
component is activated and the "-" symbol means that the system
component is deactivated. "ON" or "OFF" means that the system
component is already on or off, or, in some instances, is turned on
or off in that decision step. The asterisk "*" symbol indicates a
system parameter that is monitored and may trigger the activation
or deactivation of a system component. "IF" indicates a system
parameter that is monitored and must be satisfied to allow the
activation or deactivation of a system component. After activating
or deactivating a system component as shown in FIGS. 3-5, System
Control 100 waits two minutes before making further system changes
as provided in the tables.
[0066] Referring to FIG. 3, when the System Control 100 receives a
call for heat from the indoor air thermometer (AIR-W) and the
outdoor temperature (OT) is high (>55.degree. F.), System
Control 100 activates the indoor air blower 44 on low speed and
requests Stage Code 1 (primary compressor 12 on low) from the HPM
102, as shown in Line 1. System Control 100 then monitors the
system parameters to determine if changes to the system should be
made to increase the BTU's delivered to the indoor air space or to
improve system performance and efficiency.
[0067] As shown in Line 2 of FIG. 3, if the temperature of the air
at the indoor air blower (ST) exceeds the medium set point, System
Control 100 activates the buffer tank pump 38 to divert energy to
the buffer tank 40. As shown in Line 3, if ST falls below the low
temperature set point, meaning that energy is needed to heat the
indoor air space, the buffer tank pump 38 is terminated. If the
temperature of the water being circulated to the buffer tank
exceeds 105.degree. F., as shown in Line 4, the blower speed is
increased to medium to divert energy to the indoor air space. If ST
exceeds the high temperature set point or the water being
circulated to the buffer tank exceeds 105.degree. F., as shown in
Line 5, the indoor blower is set to high to divert additional
energy to the indoor air space. If the indoor thermostat 112
remains unsatisfied after 45 minutes (MU2), as shown in Line 6,
System Control 100 sets the blower speed to high and requests Stage
Code 2 (primary compressor 12 set to high) from the HPM 102.
[0068] Referring to FIG. 4, when the System Control 100 receives a
call for heat from the indoor air thermometer (AIR-W) and the
outdoor temperature (OT) is medium (<55.degree. F. and
>20.degree. F.), System Control 100 activates the indoor air
blower 44 on medium speed and requests Stage Code 2 (primary
compressor 12 on high) from the HPM 102, as shown in Line 7. Then,
as shown in Line 8, if the temperature of the air at the indoor air
blower (ST) exceeds the medium set point, System Control 100
activates the buffer tank pump 38 to divert energy to the buffer
tank 40. As shown in Line 9, if ST falls below the low temperature
set point, the buffer tank pump 38 is terminated. If the
temperature of the water being circulated to the buffer tank 40
exceeds 105.degree. F., as shown in Line 10, the blower speed is
increased to high to divert energy to the indoor air space. If the
indoor thermostat 112 remains unsatisfied after 45 minutes (MU2),
as shown in Line 11, System Control 100 sets the blower speed to
high and requests Stage Code 3 (primary compressor 12 set to high
and booster compressor 14 activated) from the HPM 102.
[0069] Referring to FIG. 5, when the System Control 100 receives a
call for heat from the indoor air thermometer (AIR-W) and the
outdoor temperature (OT) is low (<20.degree. F.), System Control
100 activates the indoor air blower 44 on high speed, requests
Stage Code 3 (primary compressor 12 on high and booster compressor
activated) from the HPM 102 and leaves the water heater pump 30
off, as shown in Line 12. System Control 100 then steps down the
table in progressive steps as needed.
[0070] As shown in Line 13, if the temperature of the air at the
indoor air blower (ST) exceeds the high set point, System Control
100 activates the water heater pump 30 to divert energy to the
water heater 32 to provide heat for water heating. As shown in Line
14, if ST then falls below the medium temperature set point, the
water heater pump 30 is terminated. As shown in Line 15, if ST
exceeds the high set point, System Control 100 activates both the
buffer tank pump 38 and the water heater pump 30. As shown in Line
16, if ST drops below the medium set point when both the buffer
tank pump 38 and the water heater pump 30 are running, both are
deactivated. Referring to Line 17, if the temperature of the water
being circulated to the buffer tank 40 exceeds 105.degree. F., the
buffer tank pump 38 and the water heater pump 30 are activated.
Referring to Line 18, if the indoor thermostat remains unsatisfied
after 15 minutes (MU1) with the ST temperature below the high set
point, auxiliary heating is activated at low output and the buffer
tank pump 38 is activated. Referring to Line 19, if the addition of
the low output auxiliary heating fails to satisfy the indoor
thermostat 112 after 45 minutes (MU2), high output auxiliary
heating is activated and the buffer tank pump 38 is deactivated.
Finally, as shown in Line 20, if the ST temperature exceeds the
high set point, both the buffer tank pump 38 and the water heater
pump 30 are activated.
[0071] The system may also be activated when the buffer tank 40
requires heating. As noted above, the hydronic floor heating system
36 includes a thermostat (LOOP-W) 113 that activates the pump 42
and notifies System Control 100 when the hydronic loop 43 requires
heat. System Control 100 then waits three minutes. This delay
allows the water to circulate from the buffer tank 40 to the
hydronic loop 43 before determining whether the buffer tank 40
requires heating. The delay also gives the system time to
potentially divert excess energy to the buffer tank 40 under normal
operation of the system, thereby avoiding premature, unnecessary
and intermittent start up of the compressors. After three minutes,
System Control 100 continuously monitors the temperature of the
water in the buffer tank 40 through WIT 114.
[0072] If WIT is below a predetermined point, meaning that the
buffer tank 40 requires heating, System Control 100 checks whether
AIR-W is ON, which would indicate that the indoor air space
requires heating. If AIR-W is ON, indoor air heating takes
precedence over hydronic floor heating and System Control 100
continues to follow the decision steps detailed above. If AIR-W is
OFF after the delay, meaning that the indoor air space does not
require heating, System Control 100 may then activate the buffer
tank 38 to provide heat to the buffer tank 40.
[0073] With respect to the interaction of System Control 100 with
the water heater 32, the goal of the system is to utilize the third
condenser 20 rather the element 34 to heat the water in the water
heater 32 because the heat pump provides more efficient heating
that the heating element of a conventional water heater. To achieve
this goal, the water heater pump 30 runs under most conditions when
the primary compressor 12 or both compressors are running. When the
system is active, the element 34 is interrupted whenever possible
so that the third condenser 20, rather than the water heater
element 34, is providing energy to the water heater.
[0074] However, when the outdoor temperature is very low and energy
is needed to heat the indoor air space, the water heater pump 30 is
interrupted or left off. As shown in FIG. 5 at line 12, the water
heater pump 30 is left off when the system is activated upon a call
for heat at a low outdoor temperature. As shown in FIG. 5 at lines
14 and 16, the water heater pump 30 is deactivated when the
temperature of the air at the indoor air blower (ST) drops below
the medium temperature set point. As shown in FIG. 5 at lines 18
and 19, the water heater pump 30 is not run when the indoor air
thermostat 112 is not satisfied after either the short (MU1) or
longer (MU2) time period. The water heater pump 30 is also
interrupted when the temperature of the water circulating to the
water heater (WH-RT) exceeds a certain temperature (125.degree.).
(However, when Stage Code 4 is activated as explained below, the
water heater pump 30 is activated despite the high temperature of
WH-RT.) The element 34, of course, provides heat for water heating
whenever the system is not running. To achieve the goal of
utilizing heat from the third condenser 20 rather than the element
34 whenever possible, the element 34 is interrupted whenever the
system starts or stops. A timer is then started. At the expiration
of the timer, the element 34 then is allowed to decide for itself
based on its own thermometer whether to turn on and heat the water
in the water heater 32.
[0075] When the system starts, a shorter timer (30 minutes) is
started. Under normal conditions with the heat pump running, the
heat pump should provide sufficient energy to heat the water in the
water heater 32 within this time period so that, at the expiration
of the timer, the element 34 will not need to provide heating.
However, if a significant amount of hot water is being used, the
element 34 may provide additional heating at the expiration of the
timer.
[0076] When the system stops, a longer timer (120 minutes) is
started. This timer prevents the element 34 from activating at the
end of a heat pump cycle when the system may be restarting within a
short time period. If the system does not restart, however, heating
control is returned to the element and the conventional water
heater thermostat.
[0077] The element deactivation timer at system shutdown should
typically be longer than the element deactivation timer at system
startup. At system startup, the system is providing heat to the
water heater. The timer may be shorter so that the element can
determine whether supplemental heating is required, such as, for
example, when someone is draining the hot water and the heat pump
cannot keep up. The inventor currently contemplates setting the
shutdown timer at 120 minutes and the startup timer at 30 minutes,
but these settings depend on the water heater tank size, household
domestic hot water use and other factors.
[0078] Element interrupts may also be incorporated based on the
outside air temperature (OT). At temperatures above 0.degree. F.,
the heat pump system should provide sufficient heating for water in
the water heater 32 under all system conditions so that element
heating is never required. At temperatures below 0.degree. F.,
however, the system may require that energy be diverted from the
water heater 32 to the indoor air space for to satisfy indoor air
comfort requirements. As a result, element heating of the water for
domestic use may be more frequently required. Thus, at low outdoor
temperatures, the element 34 is not interrupted and the element is
free to cycle on its own internal thermostat.
[0079] As noted above, the HPM 102 may override the system
parameters set by System Control 100 and provide internal control
of the system components and compressors. These overrides may occur
to prevent unsafe operating conditions or to increase the operating
efficiency of the system.
[0080] First, whenever the system generates a high pressure 68 (HP)
greater than 420 psig or a high temperature 70 (HT) greater than
200.degree. F. at the outlet of the primary compressor, the HPM 102
overrides whatever Request Stage Code has been determined by System
Control 100 and activates Stage Code 4. Stage Code 4 activates the
buffer tank pump 38 and the water heater pump 30 for thirty seconds
if they are not already activated. Activation of these pumps draws
energy from the system in an attempt to prevent the pressure and
temperature from going over limit and utilizes this excess energy
for the hydronic floor heating system 36 and/or the water heater
32. Thus, Stage Code 4 operates as a safety control while
simultaneously increasing the efficiency of the system.
[0081] Second, the HPM 102 constantly calculates a high side/low
side (HI/LO) pressure ratio to further control the system. For the
high side pressure, the HPM 102 reads the pressure transducer at
the outlet of the primary compressor (HP). For the low side
pressure, the HPM 102 reads the temperature at the evaporator (ET)
and converts this reading to pressure using the formula
P=A+BT+CT.sup.2+DT.sup.3 where P=pressure [bar], T=temperature [K]
and A, B, C & D are constants (For R410A: A=-195.3, B=2.58,
C=-0.01165 and D=18.02E-6).
[0082] Using this HI/LO pressure ratio, if System Control 100
requests Stage Code 1 operation and the pressure ratio is greater
than 5.5 (averaged over 10 seconds), the HPM 102 converts to Stage
Code 2 and operates the primary compressor 12 at high speed. If
System Control 100 requests Stage Code 2 operation and the pressure
ratio is greater than 6.5 (averaged over 10 seconds), the HPM 102
converts to Stage Code 3 operation and activates the booster
compressor 14.
[0083] Third, the HPM 102 monitors the evaporating temperature of
the refrigerant at the evaporator (ET) at all times to ensure that
the compressors are always running in an efficient mode. Based on
input from ET, the HPM may override a stage code request from
System Control that would place the system in an inefficient
operating mode.
[0084] Fourth, as safety controls, the HPM 102 will decrease the
Stage Code (converting from Stage Code 3 to 2, or from Stage Code 2
to 1) if the system generates a pressure (HI) greater than 500 psig
or a temperature (HIT) greater than 220.degree. at the outlet of
the primary compressor. Thus, the HPM 102 attempts to address a
high pressure or high temperature condition by reducing the output
of the compressors before taking more drastic steps.
[0085] As further safety controls, if the system generates a
pressure (HI) greater than 520 psig or a temperature (HIT) greater
than 230.degree. F. at the outlet of the primary compressor, the
HPM 102 performs a "soft hold," which is an auto reset of the
system. Under this condition, the entire system shuts down, resets
and starts up again. The HPM 102 will also perform a soft hold if
the primary compressor exceeds 30A during a heating cycle or if the
amps of the primary compressor increase more than 30% in 10
seconds. A soft hold may also be initiated in defrost mode if the
temperature (FT) of the refrigerant entering the first condenser 16
is below a predetermined point to prevent potential freeze-up
during defrost. The system hardware may also perform a "hard hold,"
or complete system shut down, if the system generates a pressure
(HP) greater than 600 psig or a temperature (HT) greater than
250.degree. F. at the outlet of the primary compressor. The HPM 102
will also perform a hard hold if three soft hold restarts occur
within 12 hours.
[0086] In addition to controlling the system compressors to
maximize the efficiency and safety of the system, the HPM 102 also
controls the economizer 22 to further optimize performance of the
system. The HPM 102 precisely regulates the flow of refrigerant
through the economizer 22 based on the temperature or pressure of
the refrigerant leaving the primary compressor 12. Starting at 440
psig (HI), the HPM 102 opens the expansion valve 46 2% to provide a
flow of refrigerant through the economizer. Then, for each increase
in pressure of 4 psig, the HPM 102 opens the expansion valve 46 an
additional 2%. Thus, for example, at 460 psig, a 22% injection flow
is provided. The HPM 102 also reads the temperature at the primary
compressor outlet (HIT) and, starting at 170.degree., opens the
valve 46 diverting flow to the economizer 2% for every 3.degree.
increase in temperature. This causes, for example, an injection of
18% at 194.degree. F. The actual injection is the larger of the two
percentages that result from the HPM's calculations.
[0087] With respect to the control of the system in cooling mode,
the system is activated when the indoor thermostat 112 calls for
cooling. In cooling mode, the booster compressor 14 is not used.
The primary compressor 12 is used at low speed (Stage Code 5) or
high speed (Stage Code 6) if additional cooling capacity is
required. Stage Code 6 may be activated after a predetermined time,
preferably 90 minutes, if Stage Code 5 fails to satisfy the
thermostat (AIR-Y).
[0088] In cooling mode, all pressure and temperature calculations
are disabled. However, the HPM 102 will convert from Stage Code 6
operation to Stage Code 5 operation if the system generates a
pressure (HP) greater than 480 psig or a temperature (HT) greater
than 200.degree. F. at the outlet of the primary compressor. The
HPM 102 will also perform a soft hold if the temperature at the
outlet of the primary compressor (HIT) exceeds 230.degree. F., the
primary compressor 12 exceeds 30A during a heating cycle or the
amps of the primary compressor increase more than 20% in 20
seconds. The safety settings for a hard hold also remain
active.
[0089] The HPM 102 may activate the defrost mode one of three ways.
First, if the outside temperature (OT) has been 40.degree. F. or
less for 2 hours of cumulative system run time or 15.degree. F. or
less for 4 hours of cumulative system run time, the defrost cycle
is activated. Second, the evaporator 24 includes a pressure
differential switch that may activate the defrost cycle. Third, the
defrost cycle may be manually activated. During a defrost cycle,
the system disables all compressor, pressure and staging
calculations and decisions.
[0090] When defrost mode is activated, the compressors 12 and 14
and the outdoor fan 51 are turned off and the buffer tank pump 38
is activated. After thirty seconds, the 4-way valve 26 is reversed
and the primary compressor 12 is activated. As described above, the
refrigerant then flows through the first condenser 16 to transfer
heat from the buffer tank 40 to the refrigerant that is cycled to
the evaporator 24 to defrost the coil. At the end of the defrost
cycle, the outdoor fan 51 is turned back on, the 4-way valve 26 is
reversed and the buffer tank pump 38 is turned off or allowed to
return to whatever mode it was in prior to the defrost cycle.
[0091] The present invention is also compatible and easily
integrated with utility Load Management Control. Load Management
Control, or LMC, allows a utility company to remotely and
temporarily shut down certain users' heating and cooling systems at
times when the utility is experiencing peak loads. This flexibility
in addressing peak load conditions is a great advantage to utility
companies. In exchange for the right and ability to remotely shut
down a user's heating and cooling system, a utility company will
typically provide reduced electricity rates, which is of course an
advantage to the consumer.
[0092] To enable the Load Management Control function, the system
includes a remote receiver or communication device provided by the
utility company. The utility company may communicate with the
remote receiver via a telephone line, radio waves, the internet or
other means. The remote receiver is integrated with System Control
100 so that, when the remote receiver receives a signal from the
utility company, the remote receiver instructs System Control 100
to place the heating and cooling system on standby. System control
100 then shuts down the system (including any auxiliary electrical
heating) for a set period of time, or until a restart signal is
received from the utility company through the remote receiver.
[0093] An auxiliary heating system 120 with a different energy
source, such as a gas furnace, is typically provided to provide
heat when Load Management Control initiates a system shut down in
cold weather conditions. This backup heating source is an integral
part of the system and controlled by the System Control 100. By
providing this control, the system can easily transition to the
backup heating source when a shut down command is received, and
also easily transition back to the main heating system when the
shut down condition terminates.
[0094] The present system is designed to provide three
outputs-forced air heating and cooling for an indoor air space,
water heating for a hydronic heating system and water heating for a
conventional tap water heater. As noted above, the novel system
configuration and control diverts energy among these three outputs
to maximize comfort, increase system efficiency, control high
system load conditions, maximize compressor run times and utilize
excess system energy. Although the preferred embodiment of the
present invention utilizes three outputs to achieve these goals,
these goals may also be achieved with only two of the three
outputs. Thus, alternative embodiments of the present invention
include systems with forced air heating and cooling combined with
hydronic floor heating, forced air heating and cooling combined
with tap water heating and hydronic floor heating combined with tap
water heating.
[0095] Other alterations, variations and combinations are possible
that fall within the scope of the present invention. For example,
as described above, the System Control may be integrated into a
single computer or controller and remain within the scope fo the
present invention. Although the preferred embodiments of the
present invention have been described, those skilled in the art
will recognize other modifications that may be made that would
nonetheless fall within the scope of the present invention.
Therefore, the present invention should not be limited to the
apparatus and method described. Instead, the scope of the present
invention should be consistent with the invention claimed
below.
* * * * *