GB1558733A - System for solar heating of a liquid - Google Patents
System for solar heating of a liquid Download PDFInfo
- Publication number
- GB1558733A GB1558733A GB575/78A GB57578A GB1558733A GB 1558733 A GB1558733 A GB 1558733A GB 575/78 A GB575/78 A GB 575/78A GB 57578 A GB57578 A GB 57578A GB 1558733 A GB1558733 A GB 1558733A
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- GB
- United Kingdom
- Prior art keywords
- collector
- temperature
- liquid
- conduit
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 31
- 239000007788 liquid Substances 0.000 title claims description 52
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 87
- 230000005855 radiation Effects 0.000 claims abstract description 8
- 238000003860 storage Methods 0.000 claims description 61
- 230000008014 freezing Effects 0.000 claims description 11
- 238000007710 freezing Methods 0.000 claims description 11
- 238000009434 installation Methods 0.000 claims description 9
- 238000012546 transfer Methods 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 5
- 238000009826 distribution Methods 0.000 claims description 4
- 238000013459 approach Methods 0.000 claims description 3
- 239000000654 additive Substances 0.000 claims description 2
- 230000002528 anti-freeze Effects 0.000 claims description 2
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 230000007613 environmental effect Effects 0.000 claims description 2
- 239000011810 insulating material Substances 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 230000002035 prolonged effect Effects 0.000 claims description 2
- 239000013589 supplement Substances 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 abstract description 2
- 238000005338 heat storage Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000005276 aerator Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000003252 repetitive effect Effects 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 239000008236 heating water Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000003223 protective agent Substances 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D11/00—Central heating systems using heat accumulated in storage masses
- F24D11/002—Central heating systems using heat accumulated in storage masses water heating system
- F24D11/003—Central heating systems using heat accumulated in storage masses water heating system combined with solar energy
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
- F24S40/60—Arrangements for draining the working fluid
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B10/00—Integration of renewable energy sources in buildings
- Y02B10/20—Solar thermal
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Pump Type And Storage Water Heaters (AREA)
Abstract
The circuit includes a pump (6), for conveying water into the solar collector (8), and a hot-water reservoir for receiving the water flowing back from the solar collector. The hot-water reservoir comprises a lower preheater (1) and an after-heater (2) arranged thereabove. Via a changeover valve (10), a control unit (36) regulated by temperature sensors (37) connects the circuit either to the preheater (1) or to the after-heater (2). The system can be used to treat service water or, in addition, for heating purposes and is equipped with an electric, supplementary heating means (35). Direct connection of the solar connector to the hot-water reservoir avoids losses caused by a heat exchanger. Even weak solar radiation can be utilised by the two-stage hot-water reservoir. <IMAGE>
Description
(54) SYSTEM FOR SOLAR HEATING OF A LIQUID
(71) We, GEORG FISCHER AKTIENGES
ELLSCHAFT, a Swiss company, of 8201 Schaffhausen, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relaes to an improved installation for the use of solar energy for the purpose of heating a liquid such as water.
The use of solar energy for the heating of service water and in heating plants has received considerable attention in recent years and various embodiments thereof have been produced which differ, primarily, in the manner in which the liquid is circulated through a solar collector, in the manner of disposing the collector, and in the delivery of heat to the service water system or to the heating plant.
In this context, the term "service water" is used to mean the provision of heated water for use as such, as distinguished from the conduction of water through a heat exchanger for space heating.
In one such embodiment, a pump conveys a heat carrier medium into a solar collector where it is heated and from which it flows back into heat storage which is equipped with heat exchangers for the heating of service water and/or heating water.
The heat carrier medium of the solar collector circuit must be selected so that no limitations are imposed with regard to the range of temperatures desired. Since water is used primarily as a heat carrier medium, protective agents must often be added to prevent freezing, but the addition of such agents decreases the heat conductivity of the water and, furthermore, in the event of some kind of leak, the addition of such agents tend to contaminate the environment. Furthermore, an indirect heat transfer by means of heat exchangers is necessary for the heating of service water if such agents are used in the heat exchange medium, and such heat exchangers decrease the efficiency of the system due to heat loss.
Also, in the case of known systems, solar heat, which can under some circumstances, cause a lower temperature on the collector than the temperature already present in the heat storage container may not be properly utilized as a result of which a considerable part of the available solar energy is lost. In another known embodiment, two heat storage units with different temperature levels are used, one of the heat storages being always connected with the solar collector whenever its temperature exceeds a certain minimum value. However, when the temperature on the solar collector does not reach this minimum value, then the circulating heat exchanging medium is conducted to the second heat storage and therein serves for preheating, for example, of the service water while the final heating is achieved in a different manner such as by an auxilliary heating unit.In the case of this embodiment, however, just as in the case of the first mentioned known installation, the heating of the service water takes place from the solar collector circuit by indirect heat transfer such as by way of a heat exchanger, which entails corresponding losses in heat.
Accordingly, an object of the present invention is to provide an installation for solar heating of water in such a way that the losses attributable to indirect heating of service water can be avoided and, nevertheless, the use of heat obtainable at low levels of solar radiation, i.e. at a low temperature level, can be achieved.
A further object is to provide a system wherein the hot water storage is subdivided into two parts including a lower preheater or first storage container and a second heater or storage container disposed on top of and connected with the first container, the system including a circulatory conduit line for the two containers with each having an inlet and an outlet which can be opened or closed by means of reversing valves, the circulatory system being under the pressure of a directly connected water system.
According to the present invention there is provided a system for heating and storing a liquid using solar energy, comprising the combination of:
a solar collector having an inlet conduit, an outlet conduit, and means therein for conducting the liquid therethrough and for heating the liquid conducted therethrough as a result of exposure to solar radiation;
a first storage container having a liquid inlet conduit and a liquid outlet conduit;
a second storage container having an inlet conduit and first and second outlet conduits, the second outlet conduit being connected to the second storage container at the top thereof for withdrawing heated liquid directly from the container;
means for mounting the second storage container close to and at a higher level than the first storage container;;
means for feeding unheated liquid under pressure to the first storage container;
a first conduit for interconnecting the top of the first storage container with the bottom of the second storage container;
a second conduit for interconnecting the outlet conduit of the first storage container and the first outlet conduit of the second storage container to the inlet conduit of the collector, and the outlet conduit of the collector to the inlet conduits of the first and second storage containers to provide a system of liquid circulation therebetween;
a pump in the second conduit for circulating the liquid through the system; and
a selectively operable valve in each of the inlet and outlet conduits of the first storage container and in the inlet and first outlet conduits of the second storage container for including or excluding selected ones of the storage containers from liquid circulation in the system.
For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings, in which:
Figure 1 is a schematic diagram of a liquid heating and storage system in accordnce with the invention, showing liquid flow lines and electrical interconnections; and
Figure 2 is a temperature-time graph illustrating a manner of operation of the system of Figure 1.
As shown in the schematic diagram of
Figure 1, the system includes a preheater or first storage container 1 and a secondary heater or second storage container 2, container 2 being disposed above container 1. A conduit 5 extends between the bottom 3 of container 2 and the top 4 of container 1.
Containers 1 and 2 together form the hot storage for the installation.
The storage containers are connected in a circulatory system which includes a conveying pump 6 which conveys water as the heat carrier medium through a conduit 7 to one, or several, if desired, solar collectors 8, a single such collector being schematically illustrated in Figure 1. Conduit 7 is connected to an inlet conduit at the lower end of collector 8 and a conduit 9 is connected to the upper, outlet conduit of the collector. Thus, water from the collector flows through conduit 9 and through a non-return valve 18 and through at least one of controlled reversing valves V1 or V3 to either inlet 10 or inlet 11 into storage containers 2 or 1, respectively.The suction side of conveying pump 6 is connected to conduits 12 and 13, conduit 12 being connected to a controlled reversing valve V2 and conduit 13 being connected to a reversing valve V4, these valves being connected respectively to the outlets 14 and 15 of containers 2 and 1. In the manner of operation contemplated in the present invention, valves Vl and V2 will be open while valves V3 and V4 are closed, or else the reverse relationship is true.
Conduit 7 is connected, at an upper point near collector 8, to a controlled valve V6 which is coupled through a conduit to a drain 16. Similarly, if desired, conduit 9 is connected to the drain conduit via a drain valve V7. Valves V6 and V7 can be opened when it is necessary to drain the conduits and/ or the collector to protect them from the danger of freezing. At the highest point of the liquid circulatory system, an automatic venting device 17 is provided, this being a conventional device which opens in the case of emptying and filling the collector 8 in order to permit air to flow in or out.
The conveying pump 6 is driven in a conventional fashion by a motor 19. On the bottom 20 of storage container 1 is connected a feeder system such as the drinking water system through a line 21 with suitable valves.
Line 21 can also incIude a safety unit 22, the components of which are determined by regulations of such authorities as local building commissions, and a locking element 23.
In the top lid of second container 2 is connected a service water connecting line 25 for the direct removal of hot water from the system for use. In addition, a circulating pump 26 is shown connected to second storage container 2 by way of conduits 27 and 28 so that pump 26 can provide hot water from container 2 through a heat exchanger 29 for the purpose of transferring heat to a connecting line 30 for a space heating system. The connecting line 30 could, however, also be shifted to the inside of container 2.
Moreover, in container 2 is provided an electric auxiliary heater 31 by which the water in container 2 can additionally be heated, if necessary or desired.
The system is further supplemented by a controlled bypass valve V5 connected in a bypass line 32 which is connected in parallel flow relationship with storage containers 1 and 2 and also with valves Vl-V4. Line 32 consists of a pipe which is not thermally insulated and therefore is capable of absar- bing heat from the environment. The purpose of this bypass line is to permit some elevation of the temperature of the water in the system in the event of low outside temperature so that the water circulating through the collector 8 can be prevented from freezing. Thus, in marginal temperature conditions, draining of collector 8 through drain 16 can be frequently avoided.
The system described and shown in Figure
1 is regulated by a regulator or control unit 33 which is connected to the various valve control solenoids, pump motors and sensing devices by electrical connections illustrated as dash-dot lines in Figure 1. The system includes temperature sensors 34a, 34b, 34c and 34d, sensor 34a being connected to a metal plate 35 disposed within collector 8.
The metal plate, as schematically shown in
Figure 1, is not in direct contact with the absorber portion of the collector, but is enclosed within the collector cover and is therefore subject to temperature changes
occurring therein which are indicative of the ambient temperature at the collector and the degree of energy impinging thereon.
Sensor 34b, on the other hand, is coupled to the liquid in such a way that it is capable of producing a signal representative of the temperature of the liquid flowing out of the collector, after it has been heated. Sensors 34c and 34d are similarly coupled to the liquid in containers 2 and 1, respectively, to produce signals representative of the liquid temperatures therein, and it will be observed that these temperatures are measured near the lower portions of the containers. These various temperatures will be identified herein by subscripts which are the reference numerals for the components. Thus, temperatures T2 and T1 respectively indicate the temperatures of containers 2 and 1, while temperature T8 indicates the temperature of the liquid in the collector. Temperature Tls is that measured by sensor 34a coupled to plate 35.The sensors themselves can be any conventional form of transducer capable of producing an electrical
signal representative of a temperature change.
By suitably controlling the valves in accordance with the measured temperatures, the operation of the system can be suitably controlled, and a graphic illustration of this control is shown in Figure 2. In that figure, the sequence of events illustrated is that which will occur when the water in containers 2 and
1 are heated, with the assumption that the collector temperature T8 increases continuously, although nonlinearly, and that no hot water removal occurs during the illustrated sequence. At the bottom of Figure 2, across the horizontal axis, four segments are shown, these segments being representative of time intervals and the numerals "2" and "1" therein indicating that the containers 2 and 1 are alternately connected into the circulatory system so that the water therein is being heated during those intervals.
When the tempeature T8 at the outlet of collector 8 is higher than the temperature T2 in container 2, and when T2 is lower than a preselected "target" temperature TG which is regarded as being a suitable temperature at which the water can be used, and which can be adjustable by selection on regulator 33, then the reversing valves Vl-V4 are actuated so that valves Vl and V2 are open, permitting conduit 9 to deliver water to inlet 10 of container 2 and so that water from outlet 14 of container 2 passes through conduit 12 and the pump circulates this water through conduit 7 and the collector, container 2 then being included in the circulatory system. At the same time, valves V3 and V4 are closed, excluding container 1 from the circulatory system. This phase of the operation is illustrated by the first segment "2" illustrated in
Figure 2.
When T2 is at least equal to T01 and T8 is higher than the temperature of the water T in container 1, then the valve operation can be reversed so that valves Vl and V2 are closed and valves V3 and V4 are open, excluding container 2 from the circulatory system and including container 1. Thus, pump 6 circulates the water through the collector and container 1, heating the water in container 1 until it also reaches temperature
T,. This phase of the operation is illustrated by the second segment of Figure 2 identified as "1".
If, at this time, temperature T8 exceeds both T,, and T21 then the control unit switches the valves again so that valves V1 and V2 are open and valves V3 and V4 are closed, again connecting container 2 into the circulatory system and excluding container 1 therefrom, permitting the water in container 2 to be heated further so that it approaches the temperature T81 the difference in temperatures being a function of loss in the system. Subsequently, whenever T8 is greater than T11 the valves can again be switched to exclude container 2 from the circulatory system and include container 1, permitting the water in container 1 to be further heated so that it approaches temperature Ts also.It will be observed that, so long as no hot water is removed, the switching can be periodically cycled to maintain the temperatures in these containers as close to temperature T8 as possible.
Whenever hot water is removed from container 2 by some consumption thereof, then the valves are switched so that container 2 is included in the circulatory system and the water therein is heated first to the consump tion temperature TQ1 this being controlled by a priority switch in regulator 33, or is heated to approximately Ts after TG is reached in container 1. As a result of this provision, the priority provision of consumption of hot water in container 2 will be assured.
Two border situations can arise which require special control considerations. In one case, it can happen that the temperatures T or T2 rise to the maximum permissible temperature T11 which may be, for example, 110"C., which can occur in the absence of hot water consumption or space heating in the summertime. The other condition is when T8 drops to a preselected temperature which is regarded as the permissible minimum and which may be close to the freezing point, e.g., 2" C., which may occur in winter, particularly at night. In either instance, the drain valves
V6 and V7 are opened so that conduits 7 and 9 are coupled to drain 16, quickly emptying collector 8, with simultaneous of opening of the aerator 17 and closing of reversing valves
Vl-V4.
As an alternative solution to the situation when the temperature reaches the maximum T,11 it is possible to open drain valve V6 for a short interval, permitting a small volume of hot water to be drained out of the system, this being automatically replaced by cold water flowing in through line 21, and thereby lowering the overall temperature of the water in the system. Valves V3 and V4 could, at this time, remain open to permit entry of the cold water into container 1.
If, after draining collector 8 as a result of the temperature reaching the minimum temperature T1, the system can be reactivated at some higher temperature such as, for example, 15" C. At that time, it would be necessary to refill the collector, in which case valves V3 and V4 would first be opened to connect container 1 to circulation lines 7 and 9, valves V6 and V7 being, of course, first closed. The collector would then automatically fill, the air therefrom being vented through aerator 17. By establishing a temperature of refilling at a point 10-15" C. higher than the minimum temperature T1, it is possible to avoid frequent repetitive emptying of the solar collector.
It will be recognized that the solar collector 8 may be operated when air temperatures are below 0 C. without any danger of freezing as long as the sun's rays heat the interior of the collector above the temperature of the inflowing water and as long as those portions of the conduits exposed to the open air are sufficiently heat insulated.
Whenever the temperature Ts drops greatly and a predetermined temperature above T1, at, for example, 5 C. is reached, the bypass valve V5 can be opened coupling a bypass line 32 into the system, the reversing valves
V1-V4 being closed. Pump 6 is then operated and the water is conveyed through solar collector 8. With line 32 exposed to an interior space which is otherwise heated, and with that line lacking insulation, sufficient heat can be absorbed thereby tD keep the water from freezing, thereby avoiding frequent and repetitive emptying of the solar collector.
Pump 6 would then be switched off only when
T8 has increased to a temperature a few degrees higher, e.g., 8" C., or whenever T81 despite the heat delivered by bypass line 32, has dropped to the minimum permissible temperature of T1, necessitating emptying of collector 8.
Drain valves V6 and V7 are controlled in such a way that in case of the failure of the supply power, they will always switch to the open position so that the collector is drained.
Check valve 18 has the effect that, in the case, of the conveying pump 6 stopping, no circulation can develop as a result of convection.
This avoids the escape of heat stored in the containers 1 and 2, whichever is connected to the circulatory system, and escape of this heat through collector 8 by convection or radiation.
Furthermore, valve 18 has the effect that, upon filling up, the water always enters collector 8 from below, through line 7, so that air can escape completely through ventilation valve 17.
It will be observed that passage 5 is constructed to form a throttle point so that, as much as possible, no undesirable circulation can occur between containers 1 and 2. It will, however, be the case that water in container 1 which is warmer than water in container 2 will flow upwardly into container 2, should that situation arise.
As will be recognized, the additional electric heater 31 begins to function whenever
T2 in container 2 as well as T8 are lower than
TG. It will also be recognized that this insulation is particularly well suited for the removal of heated service water by way of line 25, but it is possible without difficulty to use the heat stored in container 2 for transfer to a space heater by line 30.
In order to avoid delays in the control of the installation due to the sluggishness of temperature measurement, it is advantageous to measure the collectorTls directly instead of, or in addition to, the measurement of T8 at the outlet of collector 8, this being the purpose of the temperature sensor 34a connected to the metal sheet 35, previously described.
Because of the fact that the piece of sheet metal 35 has no great mass or volume and is not influenced directly by the heat transfer medium, the temperature T18 is particularly suitable to control the reversing between the containers 1 and 2 and particularly the refilling of collector 8 without any "pendu lum" or over control effect occuring in the switching process.
The installation as described herein has numerous advantages, as follows:
(a) First of all, there is a greater use of heat as a result of "preheating" of the cold water in container 1 in the case of low solar radiation. In this case, the degree of effectiveness of the collector is better because of the low heat reflection occurring to the outside in consequence of low temperature differences.
(b) It is essential that no heat exchanger is required for the heated service water so that no heat losses will develop as a result of heat transfer therein, i.e., the heat obtained is delivered in the best possible manner to the
service water system. The water which flows again into the collector in circulation will, as a result of that, have a lower temperature which again improved the degree of effectiveness of the collector. This may also be made use of through the use of two solar collectors
connected in series, wherein the first collector may be equipped more cheaply, i.e., with less insulating material and with a simple cover.
(c) The distribution of the heated water in two tanks without the possibility of significant mixing and independence upon the level of temperature makes possible the maintainence of a higher, and therefore more valuable, temperature level in the "secondary" tank 2.
(d) A further advantage of the distribution of the heated water consists in the fact that it is possible, in the case of a collector temperature which lies between the temperature of the first tank and the second tank, to heat up the water in the second tank withan electric auxiliary heater and simultane
ously to preheat the water in the first tank, which can thereby be regarded as a preheater using the solar energy.
(e) The use of a smaller, secondary heater tank 2 and a larger preheater has the advantage that a smaller volume of hot service water is always made available quickly. When auxiliary electric power is used, the consume tion of such power likewise remains small as a result of the smaller volume in the secondary tank 2.
(f) In combination with a conventional oil heating system, the solar installation precedes the combination boiler. At the same time, the solar heat which is obtained often at a lower temperature level than the boiler temperature, may be obtained both in the secondary heater as well as in the preheater independently of the boiler temperature, i.e., without corresponding limitations. Beside the heating period, it will be effective to supplement the solar energy only with electrical auxilliary power and to turn off entirely the combination boiler which has a relatively low efficiency for hot water production alone.
(g) By the use of pure water in the collector circuit, i.e., without any antifreeze or any other additives, losses through decreased heat conductivity and heat capacity as well as environmental problems are avoided should a possible leak in the line develop. Pure water has the additional advantage of causing smaller losses of pressure as well as being harmless, compatible with the environment, cheap and chemically stable.
The problems of excess heat in the event of a prolonged interval without requirements for warm water, as well as the danger of freezing, are solved in a simple manner by draining off the hot water or by emptying the solar collector. Thus, it is possible to do without larger storage volumes in order to absorb the excess heat.
WHAT WE CLAIM IS 1. A system for heating and storing a liquid using solar energy, comprising the combination of:
a solar collector having an inlet conduit, an outlet conduit, and means therein for conducting the liquid therethrough and for heating the liquid conducted therethrough as a result of exposure to solar radiation;
a first storage container having a liquid inlet conduit and a liquid outlet conduit;
a second storage container having an inlet conduit and first and second outlet conduits, the second outlet conduit being connected to the second storage container at the top thereof for withdrawing heated liquid directly from the container;
means for mounting the second storage container close to and at a higher level than -the first storage container;
means for feeding unheated liquid under pressure to the first storage container;;
a first conduit for interconnecting the top of the first storage container with the bottom of the second storage container;
a second conduit for interconnecting the outlet conduit of the first storage container and the first outlet conduit of the second storage container to the inlet conduit of the collector, and the outlet conduit of the collector to the inlet conduits of the first and second storage containers to provide a system of liquid circulation therebetween:
a pump in the second conduit for circulating the liquid through the system; and
a selectively operable valve in each of the inlet and outlet conduits of the first storage container and in the inlet and first outlet conduits of the second storage container for including or excluding selected ones of the storage containers from liquid circulation in the system.
2. A system as claimed in claim 1 and further comprising:
means for sensing the temperature of the liquid in the collector;
a drain conduit connected to the inlet conduit of the collector;
a valve in the drain conduit; and
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (9)
1. A system for heating and storing a liquid using solar energy, comprising the combination of:
a solar collector having an inlet conduit, an outlet conduit, and means therein for conducting the liquid therethrough and for heating the liquid conducted therethrough as a result of exposure to solar radiation;
a first storage container having a liquid inlet conduit and a liquid outlet conduit;
a second storage container having an inlet conduit and first and second outlet conduits, the second outlet conduit being connected to the second storage container at the top thereof for withdrawing heated liquid directly from the container;
means for mounting the second storage container close to and at a higher level than -the first storage container;
means for feeding unheated liquid under pressure to the first storage container;;
a first conduit for interconnecting the top of the first storage container with the bottom of the second storage container;
a second conduit for interconnecting the outlet conduit of the first storage container and the first outlet conduit of the second storage container to the inlet conduit of the collector, and the outlet conduit of the collector to the inlet conduits of the first and second storage containers to provide a system of liquid circulation therebetween:
a pump in the second conduit for circulating the liquid through the system; and
a selectively operable valve in each of the inlet and outlet conduits of the first storage container and in the inlet and first outlet conduits of the second storage container for including or excluding selected ones of the storage containers from liquid circulation in the system.
2. A system as claimed in claim 1 and further comprising:
means for sensing the temperature of the liquid in the collector;
a drain conduit connected to the inlet conduit of the collector;
a valve in the drain conduit; and
means responsive to the temperature sensing means for operating the valve to drain the collector when the temperature reaches either of preselected maximum or minimum values.
3. A system as claimed in claim 2, wherein the valve further operates to drain the collector in the event of power failure.
4. A system as claimed in claim 1 and further comprising:
a heat exchanger disposed in a space having a temperature above the freezing point of the liquid;
a bypass conduit connecting the heat exchanger to the second conduit in parallel flow relationship with the first and second storage containers; and
a valve in the bypass conduit, the valve being openable to permit flow of liquid through the heat exchanger to heat the liquid and prevent freezing thereof when the temperature of the collector approaches the freezing point of the liquid.
5. A system as claimed in any preceding claim, wherein the means for feeding liquid is connected to the bottom of the first storage container.
6. A system as claimed in any preceding claim and further comprising:
a space heating heat exchanger; and
third conduit means interconnecting the heat exchanger with the second storage container for circulating heated liquid from the second storage container through the heat exchanger.
7. A system as claimed in any preceding claim and further comprising temperature sensing means responsive to collector temperature comprising a sheet of metal mounted in the collector and separated from the liquid conducted therethrough, and a temperature responsive transducer mounted on the sheet and operative to produce a signal representative of the temperature of the sheet.
8. A system as claimed in claim 7 and further including a plurality of transducers for separately sensing the temperatures of the liquid in the collector and the first and second storage containers and for producing signals representative of the temperatures, and control means coupled to the transducers for selectively operating the valves.
9. A system as claimed in claim 1 and substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH27777A CH610092A5 (en) | 1977-01-11 | 1977-01-11 | System for using solar energy to heat water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1558733A true GB1558733A (en) | 1980-01-09 |
Family
ID=4183320
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB575/78A Expired GB1558733A (en) | 1977-01-11 | 1978-01-06 | System for solar heating of a liquid |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS53114538A (en) |
| CH (1) | CH610092A5 (en) |
| DE (1) | DE2800173A1 (en) |
| ES (1) | ES465832A1 (en) |
| FR (1) | FR2377011A1 (en) |
| GB (1) | GB1558733A (en) |
| IT (1) | IT7867034A0 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2131527A (en) * | 1982-12-04 | 1984-06-20 | Baucalor Ag | Liquid heating apparatus and method of operating such apparatus |
| GB2451019A (en) * | 2007-07-11 | 2009-01-14 | Ec Power As | Apparatus comprising a valve for controlling the flow of hot water between water circuits |
| GB2468706A (en) * | 2009-03-19 | 2010-09-22 | Richard Arthur Brown | Water heating apparatus comprising a first tank coupled to a second tank |
| CN101949599A (en) * | 2010-09-11 | 2011-01-19 | 广东红日太阳能有限公司 | Solar water heating system energy-saving water return device for enhancing solar energy utilization rate |
| CN109990495A (en) * | 2018-01-03 | 2019-07-09 | 殷震雄 | A kind of photovoltaic solar hot-water heating system |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2441807A1 (en) * | 1978-11-16 | 1980-06-13 | Accumulateurs Fixes | METHOD FOR CONTROLLING THE HEATING OF A SPEAKER AND REGULATING DEVICE FOR THE HEATING OF A SPEAKER |
| US4397301A (en) * | 1981-08-25 | 1983-08-09 | Canadian Patents & Dev. Limited | Method of controlling a solar system collector loop |
| DE3537224A1 (en) * | 1985-10-16 | 1987-04-16 | Rainer Dipl Ing Morsch | Solar installation |
| DE3903309A1 (en) * | 1989-02-04 | 1990-08-09 | Bernhard Meucht | Ducted open-circuit solar collector installation |
| DE4112758A1 (en) * | 1991-04-19 | 1992-10-22 | Bernhard Meucht | Solar-powered domestic hot water system - has solar collector connected directly to hot water system and thermostats to control supply pump to use available heat, and to avoid overheating and frost damage |
| DE4318480A1 (en) * | 1993-06-03 | 1994-12-08 | Bernhard Meucht | Thermostatic frost protection for solar installations |
| DE19527830C2 (en) * | 1995-07-29 | 1999-02-25 | Walter Zimmerly | Process for operating a heating system and heating system |
| DE10341741C5 (en) * | 2003-09-08 | 2014-06-12 | Ritter Energie- Und Umwelttechnik Gmbh & Co. Kg | solar system |
| DE102014000672B4 (en) * | 2013-01-29 | 2015-07-23 | Ritter XL Solar GmbH | solar system |
-
1977
- 1977-01-11 CH CH27777A patent/CH610092A5/en not_active IP Right Cessation
-
1978
- 1978-01-03 DE DE19782800173 patent/DE2800173A1/en not_active Ceased
- 1978-01-06 GB GB575/78A patent/GB1558733A/en not_active Expired
- 1978-01-09 FR FR7800412A patent/FR2377011A1/en not_active Withdrawn
- 1978-01-09 ES ES465832A patent/ES465832A1/en not_active Expired
- 1978-01-10 IT IT7867034A patent/IT7867034A0/en unknown
- 1978-01-10 JP JP93778A patent/JPS53114538A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2131527A (en) * | 1982-12-04 | 1984-06-20 | Baucalor Ag | Liquid heating apparatus and method of operating such apparatus |
| GB2451019A (en) * | 2007-07-11 | 2009-01-14 | Ec Power As | Apparatus comprising a valve for controlling the flow of hot water between water circuits |
| GB2451019B (en) * | 2007-07-11 | 2012-03-21 | Ec Power As | Control of hot water |
| GB2468706A (en) * | 2009-03-19 | 2010-09-22 | Richard Arthur Brown | Water heating apparatus comprising a first tank coupled to a second tank |
| CN101949599A (en) * | 2010-09-11 | 2011-01-19 | 广东红日太阳能有限公司 | Solar water heating system energy-saving water return device for enhancing solar energy utilization rate |
| CN101949599B (en) * | 2010-09-11 | 2012-02-29 | 广东红日太阳能有限公司 | Solar water heating system energy-saving water return device for enhancing solar energy utilization rate |
| CN109990495A (en) * | 2018-01-03 | 2019-07-09 | 殷震雄 | A kind of photovoltaic solar hot-water heating system |
Also Published As
| Publication number | Publication date |
|---|---|
| CH610092A5 (en) | 1979-03-30 |
| IT7867034A0 (en) | 1978-01-10 |
| ES465832A1 (en) | 1978-09-16 |
| FR2377011A1 (en) | 1978-08-04 |
| JPS53114538A (en) | 1978-10-06 |
| DE2800173A1 (en) | 1978-07-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |