U.S. patent number 3,844,338 [Application Number 05/182,919] was granted by the patent office on 1974-10-29 for method of operating public bath and the like.
Invention is credited to Hermann Gettman, Hans Hilgemann.
United States Patent |
3,844,338 |
Hilgemann , et al. |
October 29, 1974 |
METHOD OF OPERATING PUBLIC BATH AND THE LIKE
Abstract
An enclosed bath system, having a bath chamber in which a body
of water has its surface exposed to the air in the chamber. A heat
pump, having an evaporator, a condenser and a circulating primary
heat-transfer fluid carrying thermal energy absorbd at the
evaporator to the condenser, circulates air from the chamber into
heat-exchanging relation with the evaporator and the condenser
successively whereby the evaporator abstracts heat and mositure
from the circulated air and the condenser reheats the circulated
air prior to its return to the chamber.
Inventors: |
Hilgemann; Hans
(Recklinghausen, DT), Gettman; Hermann (Wanne-Eickel,
DT) |
Family
ID: |
26878548 |
Appl.
No.: |
05/182,919 |
Filed: |
September 22, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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881152 |
Dec 1, 1970 |
3666004 |
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Current U.S.
Class: |
165/222;
4/493 |
Current CPC
Class: |
F24F
5/0071 (20130101) |
Current International
Class: |
F24F
5/00 (20060101); F24f 003/14 () |
Field of
Search: |
;4/DIG.9,160,172,173
;219/213 ;237/12,81 ;165/3 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Hornsby; Harvey C.
Assistant Examiner: Cantor; Alan
Attorney, Agent or Firm: Ross; Karl F. Dubno; Herbert
Parent Case Text
This application is a division of Ser. No. 881,152, now U.S. Pat.
No. 3,666,004.
Claims
We claim:
1. The method of controlling the temperature of an enlcosed bath
system having a housing defining a bath chamber and a body of water
having a surface exposed to the air in said chamber, said method
comprising the steps of:
heating said body of water to a temperature above a minimum bathing
temperature with low cost energy derived during periods of low
energy cost;
permitting the transfer of heat and moisture from said body of
water to the air in said chamber;
terminating the heating of said body of water during periods of
high energy cost; and
continuously abstracting heat and condensing moisture from a
portion of the air in said chamber and thereafter returning said
portion of said air to said chamber after heating said portion of
the air from which heat was abstracted and moisture condensed at
least in part with the heat energy originally abstracted from said
portion during periods of high energy cost.
2. The method defined in claim 1, further comprising the step of
operating a heat-consuming apparatus independently of said chamber
with at least part of the heat abstracted from said portion of said
air.
3. The method defined in claim 2, further comprising the step of
mixing a quantity of fresh air with said portion of said air prior
to reheating it.
Description
FIELD OF THE INVENTION
Our present invention relates to public bathing facilities of the
enclosed type and, more particularly, to a public-bath arrangement
which may include immersion baths for therapeutic purposes,
enclosed swimming-pool and steambathing facilities, ritual baths
and the like in which a warmed body of water is available for
bathing and the entire system is enclosed in a heated chamber or
structure.
BACKGROUND OF THE INVENTION
It has been proposed heretofore to provide enclosed bathing
facilities consisting of a large heated pool of water in an
enclosure in which the atmosphere is regulated to avoid chilling
the users of the bathing facility or the like. In a conventional
public bath for therapeutic or recreational purposes, for example,
the heated pool is provided within an enclosure maintained at the
desired temperature by heating means, e.g. for heating the air
drawn into the enclosure and/or radiant or convective heaters in or
along the walls of the chamber.
In one such arrangement, heating makes use of an air preparation
apparatus by means of which cold external air is drawn into the
chamber through one or more ventilator devices, e.g. motor-driven
fans, and is heated before being expelled into the bath chamber
through one or more hot-air registors. Since the air is circulated
through the chamber by being drawn in by the ventilators (and
passed from the chamber through exhaust vents and appropriate fans
or blowers), the moisture content or humidity of the heated fresh
air is generally less than the moisture content or humidity of the
air within the chamber. At the same time, a corresponding quantity
of moist or humid room air is discharged into the atmosphere. In
this manner, the desired humidity level of the air within the
bathing chamber is maintained, the level being chosen to prevent
sweating of the walls of the chamber and the consequent
deterioration of the walls. However, during cold seasons the heat
losses through the walls of the chamber, at glass and especially
masonry portions thereof, is more pronounced and the temperature of
the air in the chamber must be sustained by further heating means.
Such heating means has included, in the past, static heat surfaces
of the type provided in convection heating and radiant heating
devices, i.e. convectors and radiators. These heaters are
dimensioned to compensate for heat transmission losses so as to
maintain the desired room temperature level.
Such systems have, however, the disadvantage that, on the one hand,
relatively warm and moist air is dispelled into the atmosphere and
the thermal energy and moisture thereof is lost, while, on the
other hand, the air-heating apparatus at the intake side of the
chamber is continuously supplying heat and moisture to incoming
air. An additional disadvantage resides in the need for static
heaters of the type mentioned earlier, requiring still further
quantities of energy which must be applied at considerable
cost.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention to
provide an improved enclosed bathing installation of the general
character described and which is of reduced construction cost,
affords increased usable space, and is less expensive to operate
than therefore.
Another object of this invention is to provide an enclosed
public-bath facility for therapeutic and recreational purposes
which avoids the disadvantages discussed above and provides
increased thermal economy at minimum cost.
Yet a further object of our invention is the provision of a bathing
facility of the enclosed type in which the internal atmospheric
conditions can be controlled with ease and with considerable
economy with respect to energy supplied from without.
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter are
attained, in accordance with the present invention, with a system
in which a heating pump drawing thermal energy from the body of
bathing water serves to control the temperature of the air in the
enclosure and the humidity thereof. According to a specific feature
of our invention, the heat pump constitutes an air-preparation
apparatus including an evaporator, a compressor and a condenser
connected in the customary heat-pump circulation path. In such a
circulation, a high-volatility fluid, e.g. a Freon-type fluorinated
or fluorochlorinated hydrocarbon, is compressed and the thermal
energy produced during compression dissipated at one state of each
cycle, whereupon the liquified fluid is passed into an evaporator
at which it is reconverted to gas while taking up thermal energy
corresponding at least to the latent heat of vaporization and
derived, in accordance with the present principles, from the water
of the bath. Thereafter, the gas is compressed and the thermal
energy released is dissipated in the condenser stage.
The present invention provides that heat-exchanger means are
included in the cycle in which the heat-pump fluid is heated
indirectly by the water of the bathing pool and the thermal energy
thus absorbed is transferred to the atmosphere of the room in which
the pool of water is enclosed to regulate the temperature and
humidity of the internal atmosphere. Consequently, the moist of
humid air in the bathing chamber constitutes a primary heat storage
reservoir while the pool of water constitutes a secondary heat
storage reservoir for the heat pump. Excess thermal energy
transferred to the room air from the water pool is conserved by
retransfer to the water and the heat-pump cycle may thus serve to
cool the room air and thereby extract moisture therefrom or, as
necessary, to warm the room air. In fact, it has been found that
the heat extracted from the atmosphere heat-storage reservoir will
generally suffice to cover the heat losses through the walls of the
room and thus prevent sweating of the walls. Preferably the pool of
water is electrically heated although any other form of heating may
be used as well, depending of course upon the economics of the
situation.
According to a more specific feature of the invention, the
evaporator of the heat pump or compressor is exposed to the
atmosphere in the enclosure and withdraws excess thermal energy
from the atmosphere and thereby dehumidifies the atmosphere, while
the condenser associated with the heat pump transfers the
abstracted atmospheric heat to an energy consumer as will be
apparent hereinafter. The condenser may be used to transfer heat to
the previously cooled atmosphere and thus serves as an air-heating
means. The evaporator, within which the refrigerant fluid is
transformed from the liquid state to the vapor state, however,
functions primarily as a condenser vis-a-vis the room atmosphere
from which excess moisture is condensed. In this manner it is
possible to provide a circulation of the room air (via fans or
blowers) so that the room air passes into heating exchange with the
evaporator and condenser of the heat pump.
Alternatively, intermediate heat-transfer circulations may be
provided at each point in the heat-exchange system. Thus at either
or both of the primary heat-exchange members of the heat pump,
namely, the evaporator and the condenser, a secondary circulation
or body of a heat-exchange fluid may be provided.
A typical secondary heat exchange fluid is water, which may be in
indirect heat exchange with the refrigerant in one of the primary
members to thereafter transfer or absorb thermal energy to or from
the air within the enclosure at secondary heat-exchange members. At
these members, the room air is passed in direct heat exchange with
the secondary heat-exchange liquids and is consequently in indirect
heat-exchanging relationship with the refrigerant.
To renew the atmosphere within the enclosure, which may become
gradually depleted by the individuals using the facility, fresh air
is mixed with the air passed into heat exchange relationship with
the evaporator (either in direct, or indirect heat exchange as
previously noted). To this end, along the circulation path of the
air through the evaporator or through the secondary heat exchanger
associated with the evaporator, there will be provided one or more
ventilators communicating with the external atmosphere, the
fresh-air passage being provided with throttling flaps or like
valve means to control the proportion of fresh air drawn into this
circulation.
The water collected by condensation from the moist air at the
evaporator is returned to the water pool by a pipe and/or pump
arrangement, thereby reducing the loss of water from the bath. This
not only diminishes the energy cost of the system but also renders
the arrangement more economical in areas in which water may be
scarce.
Economical operation of the system of the present invention may
involve the use of low-cost energy at low-tariff period and the
storage thereof, in effect, for use during hightariff periods. If
the system makes use of electrical energy and the low-tariff period
is in the evening, the secondary heat-storage reservoir can be used
as an economical repository of thermal energy built up during the
evening hours whereupon the repository is drawn upon during the
subsequent high-tariff periods to provide the thermal energy
necessary for room heating and bath heating.
The low-cost energy is stored in the form of slightly excessively
heated water in the bath or pool, the thermal energy being
gradually transferred to the internal atmosphere during periods of
need. The system is especially effective in the case where
insulation of the walls of the facility is incapable of retaining
all or most of the heat used in the facility, i.e. when the walls
are composed of material of a high heat transmission coefficient
such as glass. It will be noted that prior-art facilities of this
type must make use of a heating source during hours of the
principal use of the facility to overcome the heat loss, whereas
the system of the present invention permits the use of low-cost
heat, for example, rather than high-cost energy, to raise the
temperature or store heat in the water of the bath for subsequent
transfer to the internal air as heat loss occurs through the walls.
However, even the use of electricity as the prime energy source is
economical because the total heat requirements of the system of the
present invention is much lower than comparable prior-art systems.
The bath constitutes a thermal reservoir of such high capacity as
to permit a minor rise in temperature to make available large
quantities of heat for the atmosphere.
According to still another feature of this invention at least part
of the heat evolved at the condenser of the heat pump is dissipated
in static heaters such as convectors and radiators disposed in the
bath chamber or in some other space to be heated proximal to or
remote from the bath facility.
The system of the invention thus need not exclusively be provided
for the air and temperature conditioning of the bath chamber and
associated spaces in the bath house but may allow for the control
or operation of dwelling-house heating systems, air-conditioning
installations, and water-heating systems or the like close to or
remote from the bath chamber.
To this end, the invention provides that the secondary heat storage
reservoir, i.e. the water bath and, possibly, an additional hot
water storage reservoir, constitutes the thermal reservoir for a
heat pump, the thermal energy of which is dissipated in a
room-heating system, air-conditioning system or water-heating
system of one or more structures or rooms in the vicinity of the
bath chamber, thereby eliminating the need for further thermal
energy sources.
DESCRIPTION OF THE DRAWING
The above and other objects, features and advantages of the present
invention will become more readily apparent from the following
description, reference being made to the accompanying drawing in
which:
FIG. 1 is a perspective view diagrammatically illustrating the
prior-art system of operating a public bath;
FIG. 2 is a similar view of a system in accordance with the present
invention;
FIG. 3 is a flow diagram illustrating the heat pump of this
invention as used in the system of FIG. 2;
FIG. 4 is a circuit diagram of the heat pump provided with two heat
exchangers for indirect transfer of heat in accordance with the
invention;
FIG. 5 is a circuit diagram similar to FIG. 4 and illustrating how
the system thereof may be used with a ventilation arrangement;
FIGS. 6 and 7 are Mollier diagrams illustrating the thermodynamics
of the sytem;
FIG. 8 is a circuit diagram, with portions of the bath chamber in
perspective, illustrating the system of the present invention in
somewhat greater detail;
FIG. 9 is a view similar to FIG. 1 illustrating how the arrangement
may be used for the heating of other chambers as well as the bath
chamber;
FIG. 10 is a perspective view of a bath chamber having two
convectors according to the present invention;
FIG. 11 is a vertical cross-section, in diagrammatic form, through
the convector assembly of FIG. 10; and
FIG. 12 is a view similar to FIG. 11 with the convectors positioned
somewhat differently.
SPECIFIC DESCRIPTION
In the prior art system illustrated in FIG. 1, the bathing facility
comprises a pool 2 of water contained in an enclosure 1, the
interior 1' of which constitutes a plenum of room air. The water in
the pool 2 is heated by a unit 3 represented in diagrammatic form
and comprising, for example, a heating coil 3' brought to an
elevated temperature by an external source not otherwise
illustrated.
The air in the chamber 1' is heated by a heating unit 4 represented
in diagrammatic form and mounted upon the right-hand wall 1a of the
structure. An opening 1b is provided in this wall so that a fan 4'
can draw fresh air into the chamber 1 as represented by the arrow A
and forcing fresh air through a heating register 4" into the
chamber as shown by arrow A.sub.1.
A pump 7 circulates the water contained in the pool 2 and
represented at 2', through the housing 3" around the coil 3' via a
filter 8. A valve 9 controls the amount and circulating rate of the
water from the housing 3 of the heater and a pipe returns the warm
water to the pool 2. The system illustrated in FIG. 1 may be used
for therapeutic bathing, recreational bathing and as a public or
community bath or swimming pool.
The heater 3 is generally provided to bring the temperature of the
water in the pool to about 27.degree. to 28.degree.C.
As the bath temperature increases and during use, water vapor
passes upwardly into the atmosphere of the chamber 1' and increases
the humidity of moisture content thereof beyond a predetermined
level which is selected to minimize or prevent sweating of the
walls of the chamber. This humidity level is related to temperature
in the sense that the temperature of the boundary layers of air
adjoining the wall must remain above the dew point of the moist air
in the chamber 1'.
The heater 4 then may deliver fresh air at a temperature of about
30.degree. C and corresponding to the temperature in the bath
chamber, although with the reduced moisture content of outside air.
A corresponding quantity of moisture-laden air is discharged
through an opening 1c in the opposite wall 1d of the housing
(arrows A.sub.2 and A.sub.3) by a ventilator or fan 5. The heat
loss by conduction through the walls of the structure, i.e. the
so-called transmission losses, are made up by a plurality of static
heated surfaces 6 provided at the lowest-temperature regions of the
chamber and here illustrated to be convectors or radiators.
It will be apparent that this arrangement is a thermodynamically
open system, that the level of water in the pool 2' continuously
drops as expelled air carries moisture out of the structure, and
that considerable quantities of thermal energy are lost with the
expelled air and must be made up by some external heating
source.
In FIG. 2, by contrast, the system of the present invention
provides for the chamber 101' of the bath structure 101, a
thermodynamically closed system which is represented
diagrammatically at 10 and circulates air through this closed
system (arrows B). The pool 102 is here similarly shown to contain
a body of water 102' which may serve as a heat-storage reservoir
when it is originally brought to an elevated temperature by a
water-heating system 103, 107 - 109 as previously described for the
system 3, 7 - 9 of FIG. 1. In this case, the formation of
condensate upon the walls of the structure is avoided by
dehumidification of the air within the structure during air
circulation, while, at the same time, the temperature is
maintained. Both operations are performed by a heat pump which is
represented generally at 10. The air-heating system 4, the
air-discharge system 5 and the static heating system 6 of FIG. 1,
all can be eliminated if desired, although frequently such systems
may be provided in conjunction with the system according to this
invention.
The heat pump of the present invention may be that illustrated
diagrammatically in FIG. 3 and generally designated at 10. This
system comprises a compressor 11 which is driven by an electric
motor 11' and circulates a refrigerant such as a chlorofluorinated
hydrocarbon of the Freon type.
By way of example, the compressor 11 may be designed to deliver at
its discharge side 11a, a pressure of 16 atmospheres gauge at
70.degree.C from an input of 2 atmospheres gauge at its intake side
11b. A condensor 12 is provided to dissipate heat from the
refrigerant and thereby permit the latter to liquify the heat being
passed into the atmosphere in the bath chamber as represented by
the arrow B.sub.1 which represents a flow of air from a blower or
the like diagrammatically indicated at 15' to constitute part of
the air-circulation means associated with the heat pump. The
details of the air circulation system may be those presented in
FIG. 5.
The liquefied refrigerant may then pass through an expansion valve
or pressure-reducing valve 13 to an evaporator 14 in which the
liquid or compressed gas is expanded to the lower pressure of about
2 atmospheres gauge, while abstracting heat from the room air
forced through the evaporator as represented at 15 and by the
arrows B.sub.2.
In pratice, it has been found that air having a temperature of
30.degree.C and a moisture content of 15 grams of water per
kilogram of air, may be fed through the evaporator 14 and brought
at B.sub.2 to a temperature of 10.degree.C whereupon 7 grams of
water per kilogram of air is removed. The cooled and demoisturized
air then passes through the condensor 12 and is reheated thereby to
a temperature of about 50.degree.C by heat recirculation and
finally to 64.degree.C by the thermal energy produced by
compression of the refrigerant.
As a consequence, the air emerging at B.sub.1 is demoisturized and
warmed and is mixed with the remaining air in the chamber to
preclude condensation upon the walls and compensate for
transmission losses of heat from the structure.
The system of FIG. 3 is shown to operate for the direct heat
exchange between the air in the bath chamber and the refrigerant in
the heat-pump system. In large community bathing facilities,
however, direct heat exchange of this type may not be feasible and
we prefer to make use of a secondary heat-transfer medium. FIG. 4
illustrates such an arrangement.
In FIG. 4, the electric motor 111' drives the compressor 111 to
force high-pressure fluid to the condensor 112 in which the
high-pressure refrigerant is liquefied with the abstraction of
heat. The condensor 112 here functions as a heat exchanger
transferring this abstracted thermal energy to a coil 112' through
which water is circulated in a hot-water cycle represented
generally at 17.
The hot-water cycle includes a pump 17' feeding water to the coil
112' and thereby circulating the water through a radiator 17"
through which the room air can be passed by a fan 115' as
represented by the arrows C. Heat-exchange member 17" can be a
liquid/gas heat exchanger of the type in which a multiplicity of
finned tubes contacts the hot water while air is forced through the
spaces between and around the fins of the tubes. In addition, all
or part of the thermal energy to be transferred to the air in the
bath chamber may be passed through static heaters 17a in the form
of convectors or radiators such as have been illustrated at 6 in
the system of FIG. 1 and disposed along the floor or the chamber at
the walls thereof. Valves 17b and 17c can control the portion of
the secondary heat exchange liquid supplied to the static heaters
17a and the heat exchanger 17", while a check valve 17d prevents
back flow of the secondary heat exchange liquid.
Similarly, a cold-water circulation is provided, as shown at 16, to
remove moisture from the air. The cold-water circulation includes a
coil 114' in the evaporator 114 to which the refrigerant is
supplied by a pressure-reducing valve 113, the coil 114' being
connected in circuit with the pump 13' and a liquid/gas heat
exchanger 16". This heat exchanger may be composed of finned tubes
through which the liquid is circulated and is traversed by room air
as represented by the arrows C.sub.1 and forced through the heat
exchanger 16" by a fan 115. Fans 115 and 115' constitute intake
fans for the air circulation system. Here too, the air traversing
the heat exchanger 16" is of a low temperature and low moisture
content, but is reheated in heat exchanger 17", prior to its return
to the bath chamber.
In FIG. 5, we show a corresponding arrangement in which, however,
the air circulation passing through the heat pump is represented in
broken lines and designated as 215. In this system, of course, the
heat pump members 111, 111', 112 to 114 and secondary heat exchange
circulations 16 and 17 are identical to those of FIG. 4.
An intake duct 215a is provided to admit air from a first blower
into the heat exchanger 16" as represented by the arrow D.sub.1,
the circulation path including a branch 215b leading from the heat
exchanger 16" into the main or trunk conduit 215c. The latter is
provided with a fan 215d by means of which the relatively cool but
demoisturized air is supplied to a branch tube 15e leading to the
warm-water heat exchanger 17". The discharge side of this heat
exchanger feeds a duct 215f which opens into the room to be
wormed.
To admit fresh air into the system, we provide a further branch
215g communicating with the external atmosphere and leading it to
the trunk 215c behind the fan 215d. An adjustable jalousie flap 18
is provided in branch 215g to control or throttle the flow of fresh
air into the system and thus the proportion of fresh air mixed with
the recirculated air in the duct 215. A further heating coil 19 is
provided downstream of the fan 215d for heating air recirculated
through the system in the event of failure of the heat pump 210.
The heat pump, of course, is used in a system of the type shown in
FIG. 2.
The thermodynamic considerations of the system of this invention
are illustrated in the Mollier diagrams of FIGS. 6 and 7. In
periods in which the fuel cost is low, the water in the bathing
pool or tank can be heated from a temperature of 27.degree.C to a
temperature of about 28.degree.C or slightly higher. In most
instances, for electric power, the low-tariff period corresponds to
the evening and it is economical during this time at prevailing low
electrical costs to use electrical energy to heat water in the
bathing pool. At approximately 6 a.m. the bath heating can be cut
off while the heat pump 10 is permitted to continue in operation,
it being assumed that this time corresponds substantially to an
increase in the energy rates.
The air at a temperature represented at A and plotted along the
ordinate in FIGS. 6 and 7, is passed into direct exchange with the
evaporator 14 or into indirect heat exchange therewith by, for
example, the heat exchanger 16" and is thereby cooled to point B
with a corresponding reduction in the moisture content of about 8
grams per kilogram (as plotted along the abscissa). This moisture
is returned to the bath as represented by the dot-dash line 10' in
FIG. 2. Upon passage of this cooled and demoisturized air to the
condenser 12 or the heat exchanger 17", the air is rised to the
temperature represented at state C by the thermal energy produced
at the evaporator and to the additional state D by the thermal
energy contribution of the compressor. The total temperature rise T
thus consists of the two components T.sub.a and T.sub.b
corresponding to the contribution of circulated heat recovered at
the evaporator and replaced in the air at the condenser B and
corresponding to the added quantity of thermal energy generated at
the compressor, respectively.
In the present description the term "evaporator" will be used
invariably to refer to the heat-pump member at which the
refrigerant liquid is converted to vapor in spite of the fact that
it, in effect, constitutes a condenser for the moisture in the room
air. Correspondingly, the condenser of the heat pump will
invariably be described as such in spite of the fact that it heats
the circulated air.
To operate the heat pump and especially the condensers 12, 112
economically, while preventing the temperature difference between
the moist air and the dehumidified air, which is mixed therewith
from becoming excessive, it is important to maintain the difference
between enthalpy of the refrigerant at the condenser and the
enthalpy of the demoisturized air passed therethrough at a level
determined by the condensation point of the refrigerant and
substantially constant. For this reason, it is preferred to add
fresh air to the demoisturized air circulated through the system
especially since the fresh air is generally required to replace the
diminution of oxygen. Under these circumstances, the portion of the
air subject to cooling and finding itself in the state represented
at B, may be combined with the fresh air (E) to arrive finally,
after heating, at the state represented at D' prior to its return
to the bath chamber. Throughout the foregoing considerations, it
has been a condition that the heat supplied to the air originally
derives from the bath which is heated by means other than the heat
pump.
The following Example may clarify the economic factors involved in
the present invention.
In a conventional public bath with static heating surfaces operable
both day and night to compensate for transmission losses, the
quantity of heat necessary to compensate for such losses Q.sub.T =
10,000 kcal/hr, the quantity of heat necessary to heat the fresh
air introduced into the chamber to the temperature therein is
Q.sub.L = 12,000 kcal/hr and the quantity of heat necessary to
maintain the temperature of the water bath in spite of evaporation
is Q.sub.V = 6,000 kcal/hr. The total hourly consumption is
consequently 28,000 kcal/hr and a cost of approximately $2.80 can
be estimated if low-cost oil heat is used.
A public bath of the same dimensions, operated in accordance with
the present invention, requires that the transmission loss Q.sub.T
= 10,000 kcal/hr and the vaporization energy Q.sub.V = 6,000
kcal/hr be replaced. However, the recirculation system eliminates
substantially the Q.sub.L insert requiring replacement.
Moreover, during high-energy cost, for example during the day
between 6 a.m. and 6 p.m. the Q.sub.T or transmission loss of the
system according to the present invention is replaced or drawn from
the secondary heat storage reservoir, namely, the water pool 2', by
vaporization and convective, conductive and radiative heat transfer
to the ambient air in an amount of 6,000 kcal/hr, the remaining
4,000 kcal/hr being supplied by the compressor 11 or 111. The bath
of water, however, is cooled only very slowly from its temperature
of 28.degree.C to about 27.degree.C. During the low-cost hours
from, say, 6 p.m. to 6 a.m. the following morning, the bath is
heated by an expenditure of 12,000 kcal/hr in electrical energy
while the heat pump compressor contributes an additional increment
of 4,000 kcal/hr. This suffices to bring the temperature of the
water in the pool to 28.degree.C and closes the cycle. While
electrical costs may also bring the energy requirements to, for
example $2.80 per day, there are numerous advantages to the system
of the instant invention. Firstly, the quantity of heat Q.sub.V
equals 6,000 kcal/hr is repeatedly recovered so that only 10,000
kcal/hr (Q.sub.T) need be supplied to eliminate the heat dissipated
into the atmosphere. Only 240,000 kcal/day is required whereas the
conventional system must consume 672,000 kcal/day. As the number of
glass walls and the area thereof increase in the structure, there
is a corresponding decrease in the danger that the walls will sweat
and the destructive effect of such sweating. In conventional
bathing facilities, however, the sweating must be prevented by use
of an additional 8,000 - 30,000 kcal/hr in the air heating Q.sub.L
to bring the total to 20,000 - 25,000 kcal/hr. This additional heat
consumption is completely excluded by the system of the present
invention. Practically any heat source may therefore be used with
considerable economy.
In FIG. 8, we have shown a system which permits the pool 302 and
the water 302' thereof to function as a heat storage reservoir, the
thermal energy of which may in part be used for the heating of
ancillary chambers and systems. In this enclosed bath structure
301, the means for heating the bath 302' is represented as
including an electrical heater 303 whose heating coil 303' is
energized by an external electrical source. Through the surrounding
housing 302" of this heater, the bath water may be circulated by a
pump 307 through a filter 308. A drain 307a at the bottom of the
tank and an overflow or skimmer 307b communicate with the top of
the tank for respective conduits 307a' and 307b' leading to the
inlet of the pump 307. At the outlet side, the heater 303
communicates via line 307c with the tank close to the top of the
latter. The bath 302' is heated by repeated circulation of the
liquid of the bath through the electrical heater 303'.
In this system, moreover, the heat pump 310 includes a compressor
311 driven by an electric motor 311' and feeding refrigerant to a
condenser 312 of the liquid/liquid heat-transfer type. The coil
312' of this heat exchanger, through which the secondary heat
exchange liquid is circulated, is tied in series with the pump 317'
as will become apparent hereinafter. The liquid refrigerant, after
traversing the pressure-reducing valve 313, is vaporized in the
evaporator 314 which is also of the liquid/liquid heat-exchange
type and transfers cold to a secondary fluid circulated by a pump
316' through the coil 314' thereof. In operation, therefore, the
refrigerant is drawn in a vapor state into the compressor 311 from
the evaporator 314, is compressed and partly or completely
condensed or liquefied in the condenser 312 while transfering heat
to a hot secondary fluid, before passing into the evaporator 314
where it abstracts heat from the cold secondary fluid.
The cold secondary fluid circulation is a cold-water cycle in which
the pump 316' forces cold water through the coil 314' and
thereafter through a heat exchanger 316" as described in connection
with FIG. 4. The heat exchanger 316" is, of course, in the
circulation path of air drawn from the chamber 310' above the bath
302' by a fan 315 and cooled by passage through this heat exchanger
316". The air, via duct means of the type shown in FIG. 5, is then
led to the heating unit 317" in which heat from the secondary fluid
is used to reheat the previously cooled and demoisturized air. The
fan 315' may facilitate recirculation of the air and may be used in
part to draw fresh air into the system.
The hot water for heat exchanger 317" is delivered to the latter by
a manifold system constituting the load of the secondary hot-water
system. The manifold system includes a pipe 320a forming the inlet
manifold and connected to the pump 317' via a valve 320b while the
outlet manifold is represented at 320a' and is connected via a
valve 320b' with the intake side of the coil 312' of the condenser
312. Lines 317a" and 317b" connect the heat exchanger 317" via
valves 317c and 317c' with the manifold pipes 320a' respectively.
When the valves 320b, 320b', 317c and 317c' are open, hot water
from the secondary circuit is circulated through the heat exchanger
317".
When the system of the present invention is used for the heating of
spaces apart from the bath chamber, for air-conditioning or
hot-water heating, we provide a tertiary heat-storage reservoir, in
the form of a hot-water heater 321. The hot-water heater 321 is
connected by ducts 321' and 321" with lines 316a and 316b leading
to and from the heat exchanger 316", respectively, in the
cold-water secondary circulation represented generally at 316.
Lines 321a' and 321a" further connect the outlet and inlet of the
hot-water heater 321 with the lines 317a and 317b of the hot-water
secondary circulation represented generally at 317. Mixing valves
321b and 321c are provided in the line pairs 321', 321" and 321a'
321a", respectively, to form mixtures via mixing lines 321d and
321e of hot water with cold return water.
The heater 321 is provided with an electric heating coil 321f aa
will be apparent from FIG. 8 and communicates with an expansion
vessel 321q as well as with a pressure-relief safety valve
321h.
At the hot-water circulation 317, one or more additional hot-water
consumers may be provided as is also illustrated in this Figure.
For example, we show a set of valves 306a and 306a' for connecting
the stationary heating surfaces 306 in the hot-water circuit, via
lines 306b and 306b'. The static heating surfaces 306 may be
radiators or convectors as described for the members 6 of FIG. 1.
Valve 306a and 306a' of course are connected to the lines 320a and
320a' which constitute manifolds for feeding hot water to the
consumers and returning the hot water to the heat exchanger 312 as
previously described.
Another heating unit which may be employed in accordance with this
invention, is a dwelling house hot-water space heater 322 which is
connected by valves 322a and 322a' with the manifolds 320a and
320a'. Valves 323a and 323a' feed hot water to and return it from a
heating coil 323b in a hot-water heater 323 supplying hot water via
a line 323c to the sanitary facilities of a structure within the
same building as the bath or in a building nearby. Cold water is
supplied to the heater 323 via an inlet pipe 323d and a valve 323e.
A floorheating assembly 324 is connected by valves 324a and 324a'
to the manifold.
The water 302' within the bath 302 is heated by circulation through
the electric heater 303 during the low-cost periods of electrical
power transmission to a temperature of, for example, 29.degree.C,
the electric power supply being thereafter cut off. Meanwhile, the
water in the hot-water heater 321 is brought electrically to a
temperature of about 110.degree.C.
By vaporization of a portion of the bath water into the chamber
301' above the bath, a heat and moisture transfer from the bath to
the room air is effected. This moist air, at a temperature of about
30.degree.C, is drawn by fan 315 from the bath chamber and blown
through the heat exchanger 316" where it is cooled as described
with respect to FIG. 5 to condense moisture from the air, the
condensate being returned to the bath 302'. As shown by the broken
line 315c, this cold air is now fed through the heat exchanger 317"
at which it picks up heat and is returned, somewhat demoisturized,
to the bath chamber. The heat removed from the air at heat
exchanger 316" is recovered as usable heat in the water circulation
317 which heats the available hot water to about 60.degree.C. This
60.degree.C water is available, according to this invention, to
operate a number of heating systems. For example, part of it serves
to heat the returned air in the heat exchanger 317", while another
portion is provided for heating the stationary heating elements 306
to compensate for transmission losses through the walls of the
structure.
However, especially with small bath structures, the storage
capacity of the water 302' is not always sufficient to cover the
requirements of all of the hot water consumers (306, 317", 322, 323
and 324). In this case, the hot-water source 321 is employed and
the higher-temperature water of this source may be mixed with cold
water from the cold-water cycle 316 via valves 321b and 321c. To
this end, valves 320h may be opened to permit additional hot water
from the heater 321 to reach the consumer 306, 317", 322, 323 and
324. When temperature adjustment is required, the mixing valves
321b and 321c may be used. When, for example, it is desired to
bring the temperature in the cold water cycle from about 6.degree.C
to about 12.degree.C, only an insignificant quantity of
110.degree.C water need be withdrawn from the heater 321 which,
consequently, may be relatively small.
In case of emergency, for example, upon failure of the heat pump
310, the valves 320h may be opened so that water from the boiler
321 will directly reach the heat consumers mentioned earlier until
the heat pump 310 is restored to operation. The size of the
hot-water storage and heating unit 321 must be so related to the
water volume of the bath 302' that the bath water temperature
during the higher-cost periods of power consumption, e.g. during
the 6 to 12 hours of daylight operation in the case of electric
heating, does not drop more than about 2.degree., e.g. from
29.degree. to 27.degree.C and endanger the health and comfort of
the bather.
As noted earlier, the balance of the heat requirements may be
provided by the compressor 311 although here there is a additional
contribution from the heater 321.
The heating system illustrated in FIG. 2 differs from the system of
FIG. 1 in that the hot-water heater 421 is incorporated in the
bath-water circulation. In this case, the bath chamber is
represented at 401' while the pool 402 contains the body of water
402'. Water for heating purposes is drawn from the drain 407a at
the bottom of the tank or from an overflow or skimmer 407b close to
the top of the tank and lead via lines 407b' and 407a' to a bypass
valve 409 via the common line 407'. With the valve 409 in the
proper position, the pump 407 circulates the water through a filter
408. The heater 421 is electrically heated as represented by the
heating coil 421f and is provided with the expansion chamber 421g
and blow-off valve 421h previously described. When the valve 409 is
set to connect the heater 421 in line, the water of the bath is
circulated through the heater before being returned to the bath via
line 407c. After the bath is brought to the desired temperature by
circulation of water through the heater, the valve 409 may cut off
the heater which nevertheless continues in operation to bring the
temperature to a level of, say, 110.degree.C to provide a secondary
storage which may be drawn upon as described with reference to the
heater 321.
Another difference between the system of FIG. 9 and the system of
FIG. 8 resides in the distribution arrangement 420 by means of
which the additional heat consumers are operated. At 425, for
example, we show a climatizing unit such as a heater or cooler 425
through which hot or cold water may be passed selectively. For this
purpose, the hot water cycle 417, otherwise similar to that of FIG.
8, delivers cold water from the heat exchanger 412 to a pair of
manifolds 420a and 420a'. Valves 425a and 425a' branch hot water
from the manifolds 420a and 420a' to mixing valves 425b and 425b'.
The cold-water input to these mixing valves derives from a pair of
cold water lines 426 running to the cold water cycle 416. It will
be apparent that the apparatus 425 may conduct hot water, cold
water or water of any temperature in between depending upon the
mixing valves.
At 427, there is illustrated another type of air-conditioner
assembly which may be used in accordance with the present invention
while at 428 we have represented a central air-conditioning system.
The latter system may include a preheating air/liquid heat
exchanger 429, connected by lines 429b and 429b', with the valves
429a and 429a' of the heating manifolds 420a and 420a'. A cooler
may be provided at 430 in the form of a liquid/air heat exchanger
and is supplied with coolant from the cooling cycle 416 via lines
430' and 430". An afterwarmer 431 in line with the cooler 430 and
the prewarmer 429 in the direction of air flow (arrow F) has its
lines 431b and 431b' in series with the valve 431a and 431a' of the
manifolds. A blower 428a controls the flow of air through the
central airconditioning unit.
The air-conditioning system 427 is provided with two convector-type
heat exchangers 427a and 427b arranged one above the other in the
house and above a collecting pan 427c for condensed moisture. A fan
427d is provided to blow air through the unit, namely, the
convectors 527b and 427a in succession. The system may be used in
connection with the floor-heating unit 424 of FIG. 9 so that the
air-conditioner 427 serves only to modify the temperature and
humidity of the freshly introduced air. Air-conditioning can be
carried out with but a single wall opening to admit fresh air and
without the air shafts hitherto necessary for the purpose.
Parallel to the condenser 412 of the heat pump 410, we provide a
further condenser 432 which may be connected with the city water
lines by pipes 432a and 432b. The purpose of this auxiliary
condenser is to dissipate heat from the heat pump circuit in which
it is connected at 432c when the various hot-water consumers have
been thermally saturated. Note that the convector 427a has valves
427a' and 427a" tying it to the heater manifolds, that convector
427b has a valve 427b' tying it to the cold water network and that
valves 422a and 422a' connect the usual heater 422 to the hot-water
manifold. Furthermore, it is possible to connect the city lines
directly with the hot-water circulation 417 and thereby eliminate
the additional condenser 432 while dissipating the heat as
previously described. This has, of course, the disadvantage that
the high-oxygen content of a public-water network promotes
corrosion not only of the manifold 420a and 420a', but also of the
heat consumers connected therewith.
The higher bath temperature, designed to increase the capacity of
this heat-storage reservoir, results in an increased vaporization
of water and, consequently, an increased danger of swetting of the
walls of the chamber. To this end, we have found it to be desirable
to provide, in the region of the walls of the structure
(represented as a glass wall 32) received in channels 32a, a
vertical shaft 33 open upwardly toward the wall via a grate 36 or
the like and is divided by a partition 33' into a pair of shaft
portions 33" and 33"' (FIGS. 10 and 11). At the upper part of the
shaft portion 33" closest to the wall 32, we provide a convector 34
of the finned-type type whereas a convector 35 is positioned close
to the bottom of the partition 33', somewhat further away from the
wall.
The convector 34 is connected with the heat exchanger 316", 416" .
. . , while the convector 35 may be connected with the heat
exchanger 317", 417" of the hot-water circulation system. In this
fashion, the cold convector 34 draws the moist boundary lines of
air proximal to the wall 32 downwardly and cools it to a
temperature below the dew point of the air within the chamber above
the bath so that a portion of the moisture in the air is condensed
and precipitates therefrom. a pipe 37 returns the condensed
moisture to the bath. The cooled and demoisturized air is then
drawn forwardly at the hot convector 35 and is reheated to the
desired room temperature and permitted to rise in an upwardly
flowing layer along the downwardly flowing boundary layer.
The significant advantage of this arrangement resides in the
formation of an isolation layer of warm air between the cold-air
layer along the wall and the moist air otherwise filling the room.
The duration of the air streams entering and leaving the shaft and
their relationship to the walls can be adjusted by modifying the
positions of the fans of the grate 36 which may be of the jalousie
type. A low-noise air-circulation blower 38 of the squirrel-cage or
similar type may, of course, be provided below the convector 35 to
promote circulation of air in streams along the walls, as has been
described.
In FIG. 12, we have shown a modification of the system of FIG. 11
which, of course, represents the arrangement of the convectors
illustrated in FIG. 10. In this embodiment, the convectors 34 and
35 are canted about their longitudinal axis to promote, for the
convector 34, a downward drift of moist air toward the lower edge
of the convector at which the lowest temperature is maintained. As
a result of the effective reduction in the air-flow cross section,
the demoisturized air (arrow G) passes into the shaft portion 33'"
at higher velocity with further acceleration by the blower 38 when
the latter is provided as shown in FIG. 10. Upon passage through
the lower edge of the convector 35, the stream receives a further
direction change to the high temperature upper edge of the
convector (arrow G) with a corresponding further reduction in flow
cross section and the corresponding increase in speed. The high
speed gas stream is thus able to flow along the entire height of
the wall. It will be apparent that the system of FIG. 8 may also be
used with the arrangements of FIGS. 10-12 in which case it may be
desired to eliminate the static heating surfaces 306. The same also
applies to the system of FIG. 9.
Finally, it may be noted that the heat pumps 310 and 410 do not
necessarily require a compressor when the cold and warm heat
exchangers 312, 412 and 314, 414 are replaced by convectors
arranged as shown, for example, in FIGS. 10 and 12 whereupon an
effective circulation of the room air through the heat pump system
is provided by convection currents.
Basically, the system described above makes use of the bath as a
main heat-storage reservoir which may provide thermal energy for
uses not associated with maintaining the atmosphere within the bath
chamber as long as the maximum cooling of the bath is maintained at
about 4.degree.C. Any additional heat source which, in the case of
the systems of FIGS. 8 and 9, is the electrically heated boiler or
hot water heater 321 and 421. When it is desired to minimize the
cooling of the bath, the auxiliary hot-water heater may be used to
supply all of the additional thermal requirements of the ancillary
devices whereas substantially all of the thermal requirements can
be provided from the thermal reservoir constituted by the bath
under some cases. For the most part, however, it is desired to
maintain the temperature drop of the bath between 1.degree. and
2.degree.C, whereupon part of the heat of the ancillary devices
will be supplied by the bath while the remainder is supplied by the
auxiliary heater. It has already been noted that bath heating may
be maintained, say, for the entire low-tariff period or may be
carried out with oil at relatively low cost while the auxiliary
heater is electrically operated even during peak tariff
periods.
The invention described and illustrated is believed to admit of
many modification within the ability of persons skilled in the art
and are, of course, intended to be encompassed within the spirit
and scope of the appended claims.
* * * * *