U.S. patent application number 12/638780 was filed with the patent office on 2011-03-10 for heat recovery system of plant using heat pump.
Invention is credited to Hoon JUNG.
Application Number | 20110056227 12/638780 |
Document ID | / |
Family ID | 43646602 |
Filed Date | 2011-03-10 |
United States Patent
Application |
20110056227 |
Kind Code |
A1 |
JUNG; Hoon |
March 10, 2011 |
HEAT RECOVERY SYSTEM OF PLANT USING HEAT PUMP
Abstract
Disclosed is a heat recovery system of a plant using a heat pump
that absorbs some heat energy wasted from a condenser of the plant.
The heat recovery system is constructed such that water condensed
by the condenser is supplied to a service water heater via
condensate pumps. A heat pump is installed between the condensate
pumps and the service water heater for receiving the condensed
water and the coolant. Some of the condensed water and the coolant,
having passed through the heat pump, are supplied to a coolant
inlet port of the condenser, and the remaining portions are
supplied to the service water heater. The condensed water supplied
to the service water heater is heated by a three way valve through
which service water heating steam is supplied. Some of the steam is
directly recovered to the condenser via a combustion air
heater.
Inventors: |
JUNG; Hoon; (Daejeon,
KR) |
Family ID: |
43646602 |
Appl. No.: |
12/638780 |
Filed: |
December 15, 2009 |
Current U.S.
Class: |
62/238.7 ;
237/56; 62/324.1 |
Current CPC
Class: |
F25B 30/06 20130101;
Y02E 20/14 20130101; F25B 27/02 20130101; Y02A 30/274 20180101 |
Class at
Publication: |
62/238.7 ;
237/56; 62/324.1 |
International
Class: |
F25B 27/00 20060101
F25B027/00; F25B 30/00 20060101 F25B030/00; F24F 12/00 20060101
F24F012/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2009 |
KR |
10-2009-0084559 |
Claims
1. A heat recovery system of a plant using a heat pump constructed
such that water condensed by a condenser in which a coolant flows
from a coolant inlet port to a coolant outlet port to condense
steam into water is supplied to a service water heater via a
plurality of condensate pumps, wherein the heat recovery system
comprises a heat pump installed between the condensate pumps and
the service water heater for receiving the water condensed by the
condenser and the coolant discharged from the condenser, the
coolant, having passed through the heat pump, is supplied to the
coolant inlet port of the condenser, the condensed water is
supplied to the service water heater and heated by a three way
valve through which service water heating steam is supplied, and
the service water heating steam, having passed through a combustion
air heater, is directly supplied to the condenser.
2. The heat recovery system according to claim 1, wherein the heat
pump is constructed so as to recover heat by directly receiving
steam from the condenser.
3. The heat recovery system according to claim 1, wherein the heat
pump is constructed so as to heat combustion air and supply the
heated combustion air to a boiler.
4. The heat recovery system according to claim 1, wherein the heat
pump is constructed so as to recover heat energy from exhaust gas
having increased temperature and to use the recovered heat energy
to heat district heating water or a fuel system.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat recovery system of a
plant using a heat pump. More particularly, the present invention
relates to a heat recovery system of a plant using a heat pump that
is capable of absorbing some heat energy wasted from a condenser of
the plant, thereby improving power generation efficiency of the
plant.
[0003] 2. Description of the Related Art
[0004] As is already well known, a heat pump is a kind of
technology that is widely applicable to production equipment of an
industrial field, including refrigerators and freezers. The heat
pump performs effective heat exchange with a high coefficient of
performance (COP). Therefore, the heat pump is capable of
effectively absorbing heat energy from the atmosphere, rivers, or
industrial equipment that generates waste heat. In the most cases,
the heat pump is used for cooling purposes although the heat pump
is used for heating purposes in some cases. With the recent
increase of interest in energy efficiency, technology for improving
heat efficiency simultaneously using cooling and heating functions
is gradually increasing.
[0005] The present invention relates to a heat recovery system that
is capable of partially absorbing a large amount of heat energy
wasted from a condenser of a plant using such a heat pump, thereby
improving efficiency of the plant.
[0006] Meanwhile, a heat efficiency improvement apparatus of a
plant using a thermoelectric element is disclosed in Korean Patent
Application No. 2009-58580, which has been filed in the name of the
applicant of the present application. The disclosed apparatus has
an advantage in that the thermoelectric element is used, and
therefore, no mechanical drive parts are provided, thereby
achieving easy and simple application and noise prevention. On the
other hand, the disclosed apparatus has a disadvantage in that the
COP of the apparatus is excessively sensitive to temperature
difference and current ratio between a high temperature part and a
low temperature part, and therefore, the increase of the COP is
limited, whereby it is difficult to apply the apparatus to
large-scale equipment.
SUMMARY OF THE INVENTION
[0007] Therefore, the present invention has been made in view of
the above problems of the related art, and it is an object of the
present invention to provide a heat recovery system of a plant
using a heat pump that is applicable to a large-scale plant and, in
addition, is capable of recovering some heat discharged from a
condenser of the plant due to a coolant, thereby improving
efficiency of the plant.
[0008] In accordance with the present invention, the above and
other objects can be accomplished by the provision of a heat
recovery system of a plant using a heat pump constructed such that
water condensed by a condenser in which a coolant flows from a
coolant inlet port to a coolant outlet port to condense steam into
water is supplied to a service water heater via a plurality of
condensate pumps, wherein a heat pump is installed between the
condensate pumps and the service water heater for receiving the
water condensed by the condenser and the coolant discharged from
the condenser, some of the condensed water and the coolant, having
passed through the heat pump, are supplied to the coolant inlet
port of the condenser, while the remaining portions of the
condensed water and the coolant are supplied to the service water
heater, the condensed water supplied to the service water heater is
heated by a three way valve through which service water heating
steam is supplied, and some of the supplied steam is directly
recovered to the condenser via a combustion air heater.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0010] FIG. 1 is a construction view illustrating a heat recovery
system of a plant using a heat pump according to a first embodiment
of the present invention;
[0011] FIG. 2 is a view illustrating the flow of heat in the heat
recovery system according to the first embodiment of the present
invention shown in FIG. 1;
[0012] FIG. 3 is a construction view illustrating a heat recovery
system of a plant using a heat pump according to a second
embodiment of the present invention;
[0013] FIG. 4 is a construction view illustrating a heat recovery
system of a plant using a heat pump according to a third embodiment
of the present invention; and
[0014] FIG. 5(A) is a schematic view illustrating input and output
of energy into and from respective components of a plant before a
heat pump is applied to the plant, and FIG. 5(B) is schematic view
illustrating input and output of energy into and from respective
components of a plant after a heat pump of the present invention is
applied to the plant.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Now, preferred embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[0016] FIG. 1 is a construction view illustrating a heat recovery
system of a plant using a heat pump according to a first embodiment
of the present invention, and FIG. 2 is a view illustrating the
flow of heat in the heat recovery system according to the first
embodiment of the present invention shown in FIG. 1.
[0017] The heat recovery system of the plant is constructed such
that water condensed by a condenser 1 in which a coolant flows from
a coolant inlet port 1a to a coolant outlet port 1b to condense
steam into water is supplied to a service water heater 3 via a
plurality of condensate pumps 2. In this embodiment, a heat pump 4
is installed between the condensate pumps 2 and the service water
heater 3 for receiving the water condensed by the condenser 1 and
the coolant discharged from the condenser 1. The coolant, having
passed through the heat pump 4, is supplied to the coolant inlet
port 1a of the condenser 1. The condensed water is supplied to the
service water heater 3. The condensed water, supplied to the
service water heater 3, is heated by a three way valve 5 through
which service water heating steam is supplied. Some of the service
water heating steam is condensed by a combustion air heater 6, and
is then directly recovered to the condenser 1.
[0018] When the steam is condensed into water by the condenser 1, a
large amount of heat energy is wasted. In this embodiment, some of
the wasted heat energy is absorbed by the heat pump 4, and service
water is heated by the absorbed heat energy. At this time, the
amount of heat to heat the service water may be changed according
to a coefficient of performance (COP) of the heat pump 4.
[0019] Recently commercially available heat pumps have COPs of
about 2 to 10. When a heat source is sufficient, and a heating
temperature is about 15.degree. C., the heat pumps may have a COP
of 9 (Products of McQuay).
[0020] When a heat pump having a COP of 9 is used, therefore, it is
possible to heat service water with the amount of heat equivalent
to nine times the amount of electric power supplied to the heat
pump.
[0021] As the service water is previously heated, service water
heating steam may be left over. The steam has a relatively high
temperature (about 60.degree. C. or higher). After being used to
heat combustion air, the steam is recovered to the condenser 1. As
a result, the amount of heat introduced into a boiler is increased
without the additional increase of fuel, thereby improving the
efficiency of the plant.
[0022] Meanwhile, FIG. 3 is a construction view illustrating a heat
recovery system of a plant using a heat pump according to a second
embodiment of the present invention. The heat recovery system
according to the second embodiment is identical to the heat
recovery system according to the first embodiment except that the
heat pumps 4 use steam to be supplied to the condenser 1 as a
direct heat source.
[0023] In a heat recovery system of a plant using a heat pump
according to a third embodiment of the present invention as shown
in FIG. 4, service water is not heated by heat recovered to the
condenser 1 using the heat pump 4 but combustion air is directly
heated by the recovered heat such that the heated combustion air is
supplied to the boiler. At this time, it is necessary to increase
temperature difference at the same amount of heat since air has a
lower specific heat than water. When the temperature difference is
too large, however, the COP of the heat pump is lowered. For this
reason, it is expected that this embodiment exhibits a lower
increase in efficiency of the plant than the previous embodiments
in which the service water is heated.
[0024] FIGS. 5(A) and 5(B) are schematic views illustrating input
and output of energy into and from respective components of a plant
before and after a heat pump is applied to the plant,
respectively.
[0025] For example, when the present invention is applied to a
plant having a boiler efficiency of 90%, a turbine efficiency of
46%, and a generator efficiency of 94%, the efficiency improvement
of the plant may be estimated as follows. Before the heat pump is
applied to the plant as shown in FIG. 5(A), the total efficiency of
the plant=boiler efficiency.times.turbine
efficiency.times.generator
efficiency=output/input=498.923/1282.051=38.916%. After the heat
pump of the present invention is applied to the plant as shown in
FIG. 5(B), on the other hand, the total efficiency of the
plant=output/input=504.248/1282.051=39.331%. That is, an efficiency
improvement of about 0.415% is achieved. Such efficiency
improvement may save a considerably large amount of energy in a
large-scale plant.
[0026] This is possible when the entirety of the amount of
recovered heat is supplied to the boiler. For a plant in which an
air preheater is already installed, loss of exhaust gas is
increased due to the increase in temperature of the exhaust gas
during heating of the combustion air, with the result that
efficiency increase effect may be insignificant. In this case, it
is necessary to directly recover heat from the exhaust gas, the
temperature of which has been increased from about 117.degree. C.
to about 143.degree. C., and to use the recovered heat in a
predetermined process. The recovered heat may be used in the
predetermined process as follows. In a district heating system, the
recovered heat may be used to heat service water for district
heating. In a heavy oil or light oil plant, the recovered heat may
be used to preheat fuel, thereby improving efficiency of the
plant.
[0027] As is apparent from the above description, in the heat
recovery system of the plant using the heat pump according to the
present invention, some of the heat discharged from the condenser
due to the coolant is recovered to the heat pump, and the recovered
heat is reused, with the result that efficiency of the plant is
improved, thereby saving fuel and reducing the discharge of carbon
dioxide and thermal waste water.
[0028] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
DRAWINGS
[0029] FIG. 1 [0030] STEAM [0031] TO SECOND SERVICE WATER HEATER
[0032] SERVICE WATER HEATING STEAM
[0033] FIG. 2 [0034] COOLANT [0035] STEAM [0036] HEATED COOLANT
[0037] SEAWATER [0038] DISCHARGE OF SEAWATER [0039] RECOVERY [0040]
CONDENSATE PUMPS [0041] HEAT PUMP [0042] SERVICE WATER HEATING
STEAM [0043] SERVICE WATER HEATER [0044] SERVICE WATER [0045]
COMBUSTION AIR [0046] COMBUSTION AIR HEATER [0047] INTO BOILER
FURNACE
[0048] FIG. 3 [0049] STEAM [0050] SEAWATER [0051] DISCHARGE OF
SEAWATER [0052] RECOVERY [0053] RECOVERY [0054] CONDENSATE PUMPS
[0055] HEAT PUMP [0056] SERVICE WATER HEATING STEAM [0057] SERVICE
WATER HEATER [0058] SERVICE WATER [0059] COMBUSTION AIR [0060]
COMBUSTION AIR HEATER [0061] INTO BOILER FURNACE
[0062] FIG. 4 [0063] COOLANT INLET PORT [0064] STEAM [0065] COOLANT
OUTLET PORT [0066] COMBUSTION AIR [0067] TO BOILER [0068] HEAT PUMP
[0069] CONDENSATE PUMPS [0070] CONDENSED WATER [0071] FIRST SERVICE
WATER HEATER [0072] ADDITION [0073] TO SECOND SERVICE WATER
HEATER
[0074] FIG. 5 [0075] (A) BEFORE APPLICATION OF HEAT PUMP [0076]
BOILER [0077] TURBINE [0078] GENERATOR [0079] CONDENSER [0080] (B)
AFTER APPLICATION OF HEAT PUMP [0081] BOILER [0082] TURBINE [0083]
GENERATOR [0084] POWER TRANSMISSION END [0085] CONDENSER [0086]
HEAT PUMP
* * * * *