GB1569325A - Creation of Inventions and Patents with Artificial Intelligence

GB1569325A – Heat pump system with heat transfer
– Google Patents

GB1569325A – Heat pump system with heat transfer
– Google Patents
Heat pump system with heat transfer

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Publication number
GB1569325A

GB1569325A
GB34178/77A
GB3417877A
GB1569325A
GB 1569325 A
GB1569325 A
GB 1569325A
GB 34178/77 A
GB34178/77 A
GB 34178/77A
GB 3417877 A
GB3417877 A
GB 3417877A
GB 1569325 A
GB1569325 A
GB 1569325A
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United Kingdom
Prior art keywords
water
heat
particles
soil
heat pipe
Prior art date
1976-08-27
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

Application number
GB34178/77A
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Electric Power Research Institute Inc

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Electric Power Research Institute Inc
Priority date (The priority date 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 date listed.)
1976-08-27
Filing date
1977-08-15
Publication date
1980-06-11

1977-08-15
Application filed by Electric Power Research Institute Inc
filed
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Electric Power Research Institute Inc

1980-06-11
Publication of GB1569325A
publication
Critical
patent/GB1569325A/en

Status
Expired
legal-status
Critical
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Classifications

F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

F28—HEAT EXCHANGE IN GENERAL

F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT

F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00

F28D20/0052—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using the ground body or aquifers as heat storage medium

F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

F24—HEATING; RANGES; VENTILATING

F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS

F24T10/00—Geothermal collectors

F24T10/10—Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground

F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES

F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS

F25B17/00—Sorption machines, plants or systems, operating intermittently, e.g. absorption or adsorption type

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

Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

Y02A30/00—Adapting or protecting infrastructure or their operation

Y02A30/27—Relating to heating, ventilation or air conditioning [HVAC] technologies

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

Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]

Y02B30/62—Absorption based systems

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

Y02E10/10—Geothermal energy

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

Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation

Y02E60/14—Thermal energy storage

Description

PATENT SPECIFICATION ( 11) 1 569 325
tn ( 21) Application No 34178/77 ( 22) Filed 15 Aug 1977 ( 19) ( 31) Convention Application No 718348 ( 32) Filed 27 Aug 1976 in ( 33) United States of America (US)
C ( 44) Complete Specification Published 11 Jun 198 ()
I ( 51) INT CL 3 F 25 D 29/( 0) O ‘t,,j’ -( 52) Index at Acceptance F 4 H G 12 G 2 L G 2 M ( 54) HEAT PUMP SYSTEM WITH IMPROVED HEAT TRANSFER ( 71) We, ELECTRIC POWER RESEARCH INSTITUTE INC a corporation organised and existing under the laws of the District of Columbia United States of America, of 3412 Hillview Avenue Palo Alto State of California 9430)3 United States of America 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 5 following statement:-
A heat pump raises the temperature level by means of work input The pump cycle may be identical with the vapour compression refrigeration system It finds particular application for air-conditioning of an air space such as a home since it employs the same equipment to cool the conditioned space in the summer and to heat it in winter This dual 10 purpose is accomplished by valving which places the low temperature evaporator in the conditioned space during the summer and the temperature condenser in the same space during the winter In effect such heat pumps heat (or cool) the interior of the buildings by refrigerating (or heating) the outdoors The principle of this operation was first described by Kelvin in 1852 15 The coefficient of performance cp, for cooling a conditioned air space is given in equation ( 1) and the coefficient cp\, for warming the space is given in equation ( 2) wherein T is the temperature in absolute degrees and the subscripts c and h refer to the cold and hot temperatures respectively.
20 refrigeration T_____ cpc = work Th T ( 1) heat delivered =_T __ 2 __ 25 cpv,= work TI, T, ( 2) 25 It is apparent from the foregoing equations that maximum performance is obtained when the temperature differential between the outside temperature and that of the conditioned space is a minimum 30 The most common source of exterior heating or cooling is the surrounding air because of its convenience However since the air heats to relatively high temperatures in the summer and cold temperatures in the winter it is the least efficient source of cooling and heating.
Furthermore, in most temperate zones the heating load is usually greater than the cooling load This leads to an imbalance in the sizing of equipment and necessitates a large high 35 horsepower compressor fitted to the heat load a supplementary heating system (electrical reistance or fuel) or a heat-storage system.
The use of well water as a heat source is more efficient than atmospheric air However.
the impurity quality quantity and disposal of water and the corrosion problems of the piping and the water have minimized the use of such systems 40 Another heat source is the use of the earth itself by laving a heat pipe of the heat pump in an underground hole and then backfilling it with soil The earth is potentially the most desirable heat source or sink because of its availabilitv and seasonal uniformity of temperature However heat transfer between the liquid in the heat pipe and the soil depends largely upon the moisture content which is related to climate conditions and 45 1 569 325 L geological formation That is, as the moisture content decreases, the thermal conductivity of the soil and thus the efficiency of heat transfer with the liquid in the heat pipe correspondingly decreases This is a particular problem during the summer months in which the moisture content decreases to a minimum due, in large part to the heating of the soil by solar energy during the longer daytime periods 5 Recently, various hydrophilic polymeric gel substances have been developed with extremely high water holding capacities One such product is described in an article entitled “Super Slurper-Compound with a Super Thirst” Agricultural Research, June 1975 (published by Agricultural Research Service USDA) It is a hydrolyzed starch polvacrvlonitrile graft copolymer One use disclosed for this material is to increase the water-holding 10 capacity of sand to enhance the top growth of crops such as oats The article states that the sand, by itself, retains only 24 grams of water compared with 317 grams of water held by the sand-gel mixture at a concentration of one part of gel to 250 parts of sand Such gels are said to absorb as high as 1 000-2000 times their weight of water.
Another type of hydrophilic gel is sold by Union Carbide under the trademark -Viterra” 15 hydrogel This synthetic material is suggested by Union Carbide to be used as an additive to the soil to assist transfer of water and nutrients to a growing plant Product literature from Union Carbide suggests that the Viterra hydrogel can retain more than twenty times its dry weight of water Another such product called ‘-Imbiber Beads” is manufactured by the Dow Chemical Company with a 27:1 holding capacity 20 All these polymers have the capacity to take in a large quantity of water without becoming dissolved The water actually penetrates the polymer network causing the size of the particle to increase, but in so doing no large pockets of water are formed which might later leak out The water is actually entrapped by the molecular structure of the polymer It is extremely difficult to squeeze out entrapped water from the polymer However water 25 can be evaporated from the polymers and the starch-based copolymer is biodegradable.
In accordance with the present invention the heat transfer of a heat pump using the ground as a heat source or sink is improved by surrounding the underground heat pipe with soil containing a plurality of water-soaked absorbent particles to provide a jacket of high thermal conductivity A preferred form of absorbent particles is a hydrophilic polymeric gel 30 material To minimize loss of water from the particles after soaking with water they may be coated with a water-permeable film and then mixed with the soil In an alternative embodiment, the particles are formed of flexible balloon-like bags filled with water without an absorbent fore Other ways to prevent loss of water from the soil surrounding the heat pipes includes laying a water-impermeable film above the pipes or completely surrounding 35 them with such film.
The present invention provides a method for increasing the heat transfer to an underground heat pipe in heat exchange relation with a heat exchanger of a heat pump for heating or cooling an air conditioned space the steps of (a) laying the heat pipe in an open hole, and 40 (b) back-filling the hole with soil in which water-absorbent particles are dispersed the particles comprising a material capable of absorbing many times its own weight of water.
and soaking said absorbent particles with water.
Preferred embodiments of the invention are now described by way of example with 45 reference to the accompanying drawings in which:
Figure 1 is a schematic block diagram of a heat pump with an underground heat pipe in contact with underground soil having improved heat transfer characteristics in accordance with the present invention:
Figure 2 is an expanded cross-sectional view of one of the coated absorbent particles of 50 Figure 1, and Figure 3 is a cross-sectional view of another embodiment of the heat pipe and underground soil combination of the present invention.
Referring to Figure 1 a block flow diagram of a heat pump 11 is illustrated in which a refrigerant fluid in line 12 is circulated through a heat exchanger 13 The heat pump may be 55 of any conventional type employed for cooling or heating a conditioned air space such as a room in a commercial or residential building A major advantage of such heat pumps is that they employ the same equipment for cooling in summer or heating in winter by appropriate shifting of valve settings to reverse the flow of refrigerant A typical heat pump includes a motor operated compressor a condenser a liquid receiver an expansion valve and an 60 evaporator Any suitable refrigerant may be employed in line 12 such as a variety of chlorofluoromefhane materials sold under the trademark “Freon” A detailed construction and operation of conventional heat pumps are set forth in the following books: Sporn et al, Heat Pumps (Wvlev & Sons 1947) and Kemler et al Heat Pumip Applications, (McGraw-Hill 1950) 65 1 569 325 Referring again to Figure 1, heat is supplied in an underground heat pipe 14 for transfer to the refrigerant in line 12 by heat exchanger 13 A liquid in pipe 14 flows in a closed loop under pressure supplied by pump 16 In the illustrated embodiment, the underground portion of pipe 14 includes a maximum surface area for heat transfer with the soil Thus, the underground portion of pipe 14 includes coils 14 a and fins 14 b In addition, the pipe is 5 arranged in a serpentine path as illustrated to further maximize the heat transfer area It is preferable to form the pipe of a material of high thermal conductivity such as copper For economy of space, it may be desirable to employ a plurality of underground heat pipes connected through a manifold to the main line which passes through heat exchanger 13.
The heat exchange liquid in heat pipe 14 should have good heat transfer properties and 10 not freeze at the coldest temperature in the climate of use Thus water may be employed in warmer climates while an anti-freeze additive mav be added to prevent freezing if necessary Brine is a suitable inexpensive heat exchange fluid for line 14 in a cold climate.
Referring again to Figure 1, a hole is dug having a bottom wall 17 and upwardly extending side walls 18 Then, a portion of pipe 14 is laid into the hole and the soil removed 15 during digging of the hole is used to bury or back-fill the heat pipe In accordance with one embodiment of the present invention, the back-fill soil 19 surrounding pipe 14 contains water-soaked absorbent particles 20 in random dispersion The absorbent particles 20 may be mixed during back-filling by spraying with a hose system.
Referring to Figure 2, in a preferred embodiment particles 20 include a central core 21 20 formed of water-impermeable material In certain environments where water loss from the soil is not excessive, it should be understood that particles 2 ‘) may comprise core 21 only without any film coating The last-named embodiment will be first described in detail.
The purpose of adding the water-soaked particles to the back-fill surrounding heat pipe 14 is to maintain a high water content in the soil throughout the year especially during the 25 hot, dry summer months Such water content greatly increases the thermal conductivity and also thermal capacity of dry soil Therefore, heat is readily transferred between heat pipe 14 and the moist ground This is accomplished not only by increasing the thermal conductivity surrounding the heat pipe, but also by increasing the effective interface between the heat pipe system and the remainder of the earth 30 The timing of soaking the uncoated absorbent particles 20 with water may be varied to suit the convenience of the crew laying the heat pipe 14 Thus the particles may be soaked prior to dispersion in the back-fill soil or during subsequent to backfilling as by pouring water into the trench at such times.
The absorbent material of particles 20) has a high capacity for water so that it can retain a 35 maximum water content in hot summer months For example the absorbent preferably is characterized by a water capacity of at least 10-20 times its dry weight It is preferably in the form of a hydrophilic water-swellable insoluble cross-linked polymeric gel material.
If the particles are not protected by coating 22 they should be sufficiently inert to the soil environment and be non-biodegradable to withstand long-term retention in the soil 40 Suitable inert absorbent materials of this type include cross-linked synthetic polymers One type is manufactured by Union Carbide Corporation under the trademark Viterra-‘ hydrogel This material is a nonionic polymer which is highly stable over long periods of time, even in high temperatures is non-biodegradable and is essentially inert to acids It is stated to have a water capacity of about 20-25 times its dry weight Another type is 45 manufactured by Dow Chemical Corporation under the name “‘Gel-Guard” and “AquaBiber” These materials are stated to be quite stable non-biodegradable and not vulnerable to acids.
A number of other solid water-insoluble sorbents that swell in water are described in a paper by Weaver et al entitled ‘Highly Absorbent Starch-Based Polymer” presented at the 50 International Nonwovens & Disposables Association Washington D C March 56 1974.
One such product is a base-hydrolyzed starch-polvacrvlonitrile graft copolymer in which the nitrile functionality has been converted to a mixture of carboxvamide and alkali metal carboxylate The paper states that after drying to the carboxylate form, this material is capable of imbibing about 700 times its own weight of deionized water 55 A particular absorbent of the general type described in the Weaver et al paper is manufactured by General Mills Chemicals Inc under the designation “SGP5025-, commonly referred to as “Super Slurper”- This product is stated to have a typical water-holding capacity of 800-1,000 ml of deionized water or 350-450) ml of Minneapolis tap water per gram of product One problem with this material is that the application of 60 high pressure disrupts the gel structure to release absorbed fluid Also, water-swollen dispersions of this product are stated to be susceptible to bacterial attack and to deteriorate on prolonged storage at room temperature.
Because of their stability and non-biodegradabilitv the Gel-Guard and Viterra hydrogel products are particularly suited for use with a protective coating 12 However, they have a 65 1 569 325 far lower water capacity than the less stable, starch-based products described in the Weaver et al paper The high capacity starch-based products may be employed by coating with a protective film of water-impermeable, non-biodegradable material as set forth hereinafter.
It should be understood that other absorbent material capable of high water retention also may be used in accordance with the present invention For example although not as 5 absorbent as polymeric gel materials certain molecular sieve materials as of the inorganic zeolite type may be employed as the absorbent material for possible special soil applications Such materials may be formed capable of binding water tightly The theory of such molecular seives is briefly disclosed at columns 3-5 of Rabinowitz U S patent 3,612,939 10 In the embodiment of Figure 2 absorbent particles 20 are formed of a suitable size for random dispersion throughout the back-fill soil It is preferable to use large particles to minimize the surface to volume ratio, and thus, the surface available for evaporation By premixing soil with relatively large particles (e g 10 cm effective diameters or more) the soil fills any void spaces created between the large particles This minimizes such void is pockets of extremely low thermal conductivity Such voids may also be filled by using some smaller particles 20 together with the larger ones To minimize evaporation and also permit uniform dispersion, it is believed that a gradation of particle sizes would be most effective.
say, with effective diameters as small as 0 5 cm to as large as 10 cm or larger The precise sizing is not critical and will depend upon the type and depth of soil A suitable soil includes 20 at least 20 % of the particles with a diameter of at least O 5 cm.
Since the object of the invention is to increase the thermal conductivity and capacity of the soil by increasing its water content, it is apparent that the absorbent materials of the present invention should be soaked with sufficient quantities of water and for a sufficient time to essentially saturate the absorbent materials In this manner the thermal 25 conductivity and capacity of the soil is maximized for a given quantity of added absorbent particles.
Referring to Figure 2 a preferred embodiment of absorbent particles 20 is illustrated in which the absorbent water-soaked core 21 is coated with a thin film 22 of material which is essentially impermeable to water and non-biodegradable in the soil 30 A major advantage of film 22 is to prevent evaporation of water from the water-soaked core material In an ideal system the coating is totally impermeable to water Thus all of the water initially present in the soaked core 21 would be retained in the back-fill soil Of course, cracks in the coating may develop during abrasion or under the pressure of the back-fill soil However even in these instances, the great majority of the core material is 35 protected from exposure to evaporation, thereby increasing the life of water retention to a major extent.
Another advantage of such coating is to protect the absorbent particle core from biological components of the soil Thus such a coating can protect a biodegradable starch-based absorbent core of the foregoing type 40 The thickness of film 22 should be sufficient to provide strength to withstand handling and the pressures created during back-filling In addition, the film should be of sufficient thickness to prevent permeation of water therethrough These characteristics are dependent not only upon thickness but also upon the type of material employed for the film In general the film of a thickness of 250 microns or less is believed to be suitable for 45 most coating materials If the coating material is characterized by a low thermal conductivity it is preferable to minimize the thickness of the film to obtain maximum benefit from the high thermal conductivity of the water-soaked absorbent core.
Suitable materials for forming the water impermeable film comprises various synthetic polymers such as polyvinyl chloride acrylic polymers polvtetrafluoroethvlene or 50 monoolefins such as polyethylene or polvpropylene Other materials such as paints or shellacs including metals or other inorganic fillers may also be employed.
In another form, coating 22 may be in laminate form and comprising two or more layers as where a single layer may not possess all of the desired properties For example, an inner hydrophilic polymer, such as polyvinyl acetate or a polyester is readily coated as a film 55 onto soaked absorbent core 21 However, it may not possess sufficient impermeability to prevent substantial evaporation of water from core 21 and may not be of a character to adequately protect the core from harmful elements in the soil Thus a second film sufficiently impermeable to protect the core and prevent evaporation such as poly vinylidene chloride may be coated readily onto the first layer but not onto the core directly 60 In a further embodiment, instead of forming a laminate to combine layers of different properties in coating 22 a single coating may be applied with modified surface characteristics For example the surface of a polystyrene film coating which is hydrophobic, may be rendered hydrophilic by grafting a hydrophilic monomer onto its surface such as a polyalkyl alcohol or polvhydroxyethyl methacrylate (HEMA) Known 65 A 1 569 325 grafting techniques may be employed such as oxidation of the film surface to create free radical sites.
One suitable coating material would be a hydrophilic polymer which maintains its structural integrity in the form of a film even in the presence of water Such a material could be sprayed with an appropriate carrier and permitted to dry on and be bonded to the 5 surface of the particles Suitable hydrophilic polymers include certain acrylic resins and, under certain circumstances, polyvinyl alcohol.
Hydrophobic polymeric materials may also be employed for the film by use of known techniques For example, core 21 could be passed through a thin, wet polymer film, say, formed of a solution of polyethylene Upon piercing of the film by core 21 a portion of the 10 film wraps around the particles and seals against itself Then the solvent is permitted to dry.
Such hydrophobic coating would not be bonded to the absorbent core.
In another technique, the absorbent soaked particles could be placed in very thin open containers of dry polymeric materials which are then sealed For example the particles may be placed into flexible bags followed by heat sealing of the bag opening Also, the 15 absorbent particles may be placed in rigid containers formed, say of two hemispheres of a thermo plastic polymer, e g, polystyrene Then, the hemispheres are sealed as by the application of heat.
The techniques of spraying a film of shellac varnish or paint onto a surface are well known For example, spray cans are available including propellants for spraying such 20 materials in a suitable carrier onto the core for rapid drying.
For uniform coating with a spray, it is preferable that the particles be rotated during spraying One technique for this purpose is to convey the particles to the top of a spray chamber and simultaneously contact them with the spray during gravitation of the particles.
In another embodiment, the particles could be sprayed on a vibratory or air bearing 25 conveyor In this embodiment, soaking and coating may be accomplished in the same system For example, the absorbent cores may pass on a conveyor through a first zone in which they are soaked with water and, thereafter through a second zone in which the film is applied.
When the absorbent particles are not protected by a film 22, it may be desirable to 30 include surfactant chemicals to reduce the rate of evaporation Such surfactants would be most beneficial for back-fill soil subjected to very hot dry temperatures such as in desert-like areas.
Referring to Figure 3, an expanded view of heat pipe 14 of Figure 1 is illustrated in combination with further means for retaining the water adjacent to coiled portion 16 a of 35 heat pipe 14 A relatively good heat transfer sheath generally denoted by the number 29 is illustrated serving, when disposed in the hole, to isolate back-fill soil 19 containing absorbent particles 20 from the surrounding soil Sheath 29 may include a roof 30 with downwardly projecting edges 30 a meeting with a bottom sheet 31 of a cross-section conforming to the adjacent hole wall Sheath 29 is formed of waterimpermeable, 40 non-biodegradable material such as a metal or synthetic polymer The edges of roof 30 and bottom sheet 31 are suitably sealed with an adhesive or where formed of a thermoplastic material such as polyethylene, may be sealed by the application of heat.
A major cause of loss of water is upward evaporation Accordingly roof 30 may be employed without bottom sheet 31 if desired Alternatively, roof 30 may be omitted 45 leaving bottom sheet 31 to prevent water removal below and to the sides of heat pipe portion 14 a.
It is preferable that sheath 29 be formed of a material which does not interfere with heat transfer to the surrounding soil For efficiency of operation it is preferable for this material to be a good heat conductor such as metal However if this is impractical due to costs, 50 synthetic polymeric materials may also be employed so long as they are not of excessive thickness so as to interfere with good heat transfer with the adjacent soil.
Sheath 29 is suitably formed by the following steps After the hole is dug, bottom sheet 31 is laid to conform to the hole walls Then pipe 14 a is laid to the interior of the sheath together with back-fill soil containing soaked absorbent particles 20 Then, roof 30 is placed 55 over the upper surface of the back-fill soil and sealed with bottom sheet 31 Finally, the remainder of the back-fill without absorbent is placed over roof 30.
Referring again to Figure 3 the soaked absorbent particles 20 are illustrated as being distributed in a concentric, compacted layer surrounding the coil in heat transfer pipe 14 a.
Thus, pipe 14 a is totally surrounded by a layer which includes a major portion of and 60 preferably consists essentially of particles 20.
A suitable sequence to accomplish the specific back-fill layering of Figure 3 is as follows.
First, the hole is dug and, optionally partially back-filled with soil containing some absorbent particles Then pipe 14 a is laid and surrounded with a layer exclusively containing absorbent particles 20 including a size gradation of sufficient small particles to 65 1 569 325 fill the voids among the larger ones Soaking of the particles may be performed by previously mentioned techniques and in one of the sequences set forth above.
The advantage of forming a layer of the preceding paragraph is illustrated by the following analysis To maximize heat removal from a heat source, it is important to concentrate the increase in thermal conductivity in the medium adjacent to the source and 5 to disperse the increase over a larger volume Applying this principle to the present invention, for a given volume of absorbent particles 20, it is preferable for a maximum increase in the heat transfer to concentrate the particles as illustrated in Figure 3 rather than to disperse them throughout the trench volume.
There may be special circumstances where the soil is preferably dispersed among 10 absorbent particles 20 For example, as set forth above, such particles may be so large that substantial air void space of low thermal conductivity would be created between particles.
Premixing with the soil would fill the voids to some extent with soil of better thermal conductivity than the air of void spaces.
In an alternative embodiment, the water soaked absorbent core of the jacketed particles 15 of Figure 2 would be replaced by liquid water In this instance, layer 22 is of sufficient strength to resist rupturing during the back-filling operation and afterwards Of course, rupturing is more critical in this water embodiment than in the foregoing absorbent core one because the liquid water would be free to run out of the rupture whereas the absorbent would retain the water under the pressure of overhead soil A suitable jacket for layer 22 is 20 a flexible balloon-like bag formed of substantially water-impermeable polymeric material.
Thus, the water could be filled into polyethylene bags of the foregoing preferred size ranges which are then heat-sealed It is important to avoid substantial air bubbles during filling which would reduce the thermal conductivity of the particles.

Claims (1)

WHAT WE CLAIM IS: 25
1 In a method for increasing the heat transfer to an underground heat pipe in heat exchange relation with a heat exchanger of a heat pump for heating or cooling an air conditioned space the steps of (a) laying the heat pipe in an open hole and (b) back-filling the hole with soil in which water-absorbent particles are dispersed the 30 particles comprising a material capable of absorbing many times its own weight of water, and (c) soaking said absorbent particles with water.
2 The method of Claim 1 in which said soaking step is performed prior to back-filling.
3 The method of Claim 1 in which said soaking step is performed by pouring water into 35 the hole during back-filling.
4 The method of Claim 1 in which said soaking step is performed by pouring water into the hole subsequent to back-filling.
The method of Claim 1 in which at least 20 % of said sorbent particles have an effective diameter of at least 0 5 cm 40 6 The method of Claim 1 in which after soaking said absorbent particles are coated with a substantially water-impermeable film of sufficient strength to withstand mixing with soil and thereafter said coated particles are dispersed in said soil prior to back-filling.
7 The method of Claim 1 in which, after steps (b) and (c), a water impermeable sheet is placed over the back-filled hole to reduce evaporation of water from said soaked absorbent 45 particles.
8 The method of Claim 1 in which said soaked particles are formed of a hydrophilic polymeric gel.
9 The method of Claim 1 in which said absorbent particles are deposited as a concentrated layer around the heat pipe without premixing with substantial back-fill soil 50 In a method for increasing the heat transfer to an underground heat pipe in heat exchange relation with a heat exchanger of a heat pump for heating or cooling an air conditioned space the steps of (a) digging a hole for the heat pipe.
(b) depositing an impermeable lower sheet with upwardly extending side walls and a 55 bottom wall to conform to the hole.
(c) laying the heat pipe in the interior of the lower sheet.
(d) back-filling around the heat pipe with soil in which water-absorbent particles are dispersed the particles comprising material capable of absorbing many times its own weight of water and (e) soaking said absorbent particles with water.
11 The method of Claim 10 in which an impermeable roof is placed over the upper surface of said back-filled soil to reduce evaporation of water from said soaked absorbent particles.
12 The method of Claim 11 in which the upper edges of said bottom sheet are sealed 65 1 569 325 with the side edges of said roof.
13 A heat pump structure for cooling or heating a conditioned air space comprising (a) a heat exchange zone.
b) a refrigerant fluid line extending through said heat exchange zone, (c) an underground heat pipe extending through said heat exchange zone, and in heat 5 exchange relation with said refrigerant fluid line, and including a heat conductive portion, (d) back-fill soil around said underground pipe heat conductive portion, and (e) a plurality of water-soaked absorbent particles dispersed in said back-fill soil, said particles comprising a material capable of absorbing many times its own weight of water.
14 The structure of Claim 13 together with an impermeable roof disposed over the 10 upper surface of the back-filled soil and heat pipe.
The structure of Claim 13 together with an elongate impermeable lower sheet with upwardly extending side walls and a bottom wall disposed below and to the sides of said heat pipe.
16 The structure of Claim 13 in which said absorbent particles form a concentrated 15 layer around said heat pipe.
17 The structure of Claim 13 in which said absorbent particles are present in a gradation of sizes sufficient for void spaces among the larger particles to be filled to a significant extent with the smaller particles.
18 A heat pump structure for cooling of heating a conditioned air space comprising 20 (a) a heat exchange zone, b) a refrigerant fluid line extending through said heat exchange zone.
(c) an underground heat pipe extending through said heat exchange zone and in heat exchange relation with said refrigerant fluid line, and including a heat conductive portion, (d) back-fill soil around said underground pipe heat conductive portion and 25 (e) a plurality of water-filled flexible water-impermeable bags dispersed in said back-fill soil.
19 The structure of Claim 18 together with an impermeable roof disposed over the upper surface of the back-fill soil and heat pipe.
20 The structure of Claim 18 together with an impermeable lower sheet with upwardly 30 extending side walls and a bottom disposed below and to the sides of said heat pipe.
21 The structure of Claim 13 in which said absorbent particles are formed of a hydrophilic polymeric gel.
22 The structure of Claim 21 in which said gel particles are surrounded by a flexible water-impermeable coating 35 23 A method for increasing heat transfer in heat pump apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
24 Heat pump apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
40 ELECTRIC POWER RESEARCH INSTITUTE INC Per BOULT WADE & TENNANT.
34 Cursitor Street.
London EC 4 A IPO.
Chartered Patent Agents 45 Printed for Her Majesty’s Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1980.
Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A LA Yfrom which copies may be obtained.

GB34178/77A
1976-08-27
1977-08-15
Heat pump system with heat transfer

Expired

GB1569325A
(en)

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

US05/718,348

US4042012A
(en)

1976-08-27
1976-08-27
Heat pump system with improved heat transfer

Publications (1)

Publication Number
Publication Date

GB1569325A
true

GB1569325A
(en)

1980-06-11

Family
ID=24885772
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB34178/77A
Expired

GB1569325A
(en)

1976-08-27
1977-08-15
Heat pump system with heat transfer

Country Status (7)

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Link

US
(2)

US4042012A
(en)

JP
(1)

JPS5348259A
(en)

CA
(1)

CA1045394A
(en)

DE
(1)

DE2738254A1
(en)

FR
(1)

FR2363063A1
(en)

GB
(1)

GB1569325A
(en)

SE
(1)

SE7709259L
(en)

Families Citing this family (83)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

US4138995A
(en)

1976-08-25
1979-02-13
Yuan Shao W
Solar energy storage and utilization

DE2700822C3
(en)

1977-01-11
1979-06-21
Uwe 2251 Schwabstedt Hansen

Method for storing thermal energy in a heat storage device and for extracting the stored thermal energy and device for carrying out the method

CH624752A5
(en)

1977-03-24
1981-08-14
Friedrich Schlatter
Heat accumulator arranged in the ground for heating a building

US4383419A
(en)

1977-05-11
1983-05-17
Bottum Edward W
Heating system and method

US4270512A
(en)

1978-03-06
1981-06-02
Maas Robert E V D
Heat storing fireplace

FR2428813A1
(en)

1978-06-16
1980-01-11
Saint Gobain

TANK FOR STORING CALORIFIC ENERGY, PARTICULARLY ENERGY PRODUCED BY SOLAR SENSORS

DK145108C
(en)

1978-06-22
1983-01-31
Krueger As I

PROCEDURE FOR USING HEAT CONTENTS IN WASTE WATER AND PLACES FOR EXERCISING THE PROCEDURE

US4240268A
(en)

1978-10-13
1980-12-23
Yuan Shao W
Ground cold storage and utilization

US4258780A
(en)

1978-12-22
1981-03-31
United Technologies Corporation
Dual cycle heat pipe-method and apparatus

US4279294A
(en)

1978-12-22
1981-07-21
United Technologies Corporation
Heat pipe bag system

US4339929A
(en)

1978-12-22
1982-07-20
United Technologies Corporation
Heat pipe bag system

US4257239A
(en)

1979-01-05
1981-03-24
Partin James R
Earth coil heating and cooling system

US4361135A
(en)

1979-05-05
1982-11-30
The United States Of America As Represented By The United States Department Of Energy
Cooperative heat transfer and ground coupled storage system

US4369635A
(en)

1979-06-25
1983-01-25
Ladek Corporation
Subterranean heating and cooling system

US4277946A
(en)

1979-08-13
1981-07-14
Bottum Edward W
Heat pump

US4283925A
(en)

1979-11-15
1981-08-18
Robert Wildfeuer
System for cooling

DE2952541A1
(en)

1979-12-28
1981-07-09
Chemowerk Erhard Mödinger, Fabrik f. Kunststofferzeugnisse, 7056 Weinstadt

DEVICE, IN PARTICULAR HEATING DEVICE, FOR THE EXPLOITATION OF EARTH HEAT WITH A HEAT PUMP

US4360056A
(en)

1980-03-19
1982-11-23
Spencertown Geo-Solar Associates
Geokinetic energy conversion

US4361661A
(en)

1980-05-22
1982-11-30
Western Electric Company, Incorporated
Thermal backfill composition method

US4327560A
(en)

1980-06-03
1982-05-04
Leon Harry I
Earth-embedded, temperature-stabilized heat exchanger

EP0041658B1
(en)

1980-06-06
1985-04-10
Alexander Kückens
Device for heating and cooling of conditioned rooms in appartments, greenhouses and the like

US4452303A
(en)

1980-08-07
1984-06-05
Wavin B. V.
Device and a method for recovering heat from the soil

US4412426A
(en)

1980-12-22
1983-11-01
Yuan Shao W
Wiser cooling system

DE3264980D1
(en)

1981-02-20
1985-09-05
Delta Rech & Dev
Method and installation for controlling the temperature in a greenhouse

US4566532A
(en)

1981-03-30
1986-01-28
Megatech Corporation
Geothermal heat transfer

US4556101A
(en)

1981-03-30
1985-12-03
Megatech Corporation
Wavy tube heat pumping

US4376435A
(en)

1981-04-08
1983-03-15
Pittman Charles D
Solar powered air conditioning system

US4747240A
(en)

1981-08-06
1988-05-31
National Gypsum Company
Encapsulated PCM aggregate

US4392531A
(en)

1981-10-09
1983-07-12
Ippolito Joe J
Earth storage structural energy system and process for constructing a thermal storage well

DE3210370C2
(en)

1982-02-11
1984-04-12
Walter Dr. 5902 Unglinghausen Helmbold

Long-term heat storage

US4516629A
(en)

1982-04-06
1985-05-14
Thermal Concepts, Inc.
Earth-type heat exchanger for heat pump system

US4570452A
(en)

1982-09-22
1986-02-18
Thermal Concepts, Inc.
Earth-type heat exchanger for heat pump systems

FR2543529B3
(en)

1983-03-29
1985-12-20
Degremont Sa

METHOD FOR RECOVERING ENERGY IN AN OZONE MANUFACTURING INSTALLATION

US4674561A
(en)

1985-03-29
1987-06-23
Kelley Norman B
Air temperature control system

JPS63116073A
(en)

1986-10-31
1988-05-20
株式会社東芝
Heat accumulation type heat pump

US5086493A
(en)

1990-02-09
1992-02-04
Steffes Paul J
Electric thermal storage boosted heat pump air heating apparatus

US5004374A
(en)

1990-02-28
1991-04-02
Bettie Grey
Method of laying out a pathway for piping

US5201024A
(en)

1990-11-26
1993-04-06
Steffes Paul J
Double loop heat storage space heating furnace using an air-to-air heat exchanger

US5243864A
(en)

1991-08-16
1993-09-14
R. J. Lee Group, Inc.
Device for collecting airborne particulate samples

US5477703A
(en)

1994-04-04
1995-12-26
Hanchar; Peter
Geothermal cell and recovery system

US5509462A
(en)

1994-05-16
1996-04-23
Ground Air, Inc.
Ground source cooling system

US5461876A
(en)

1994-06-29
1995-10-31
Dressler; William E.
Combined ambient-air and earth exchange heat pump system

US5662161A
(en)

1995-08-10
1997-09-02
The United States Of America As Represented By The Secretary Of The Navy
Breathing gas cooling and heating device

US6672371B1
(en)

1995-09-12
2004-01-06
Enlink Geoenergy Services, Inc.
Earth heat exchange system

US6860320B2
(en)

1995-09-12
2005-03-01
Enlink Geoenergy Services, Inc.
Bottom member and heat loops

US6585036B2
(en)

1995-09-12
2003-07-01
Enlink Geoenergy Services, Inc.
Energy systems

US7017650B2
(en)

1995-09-12
2006-03-28
Enlink Geoenergy Services, Inc.
Earth loop energy systems

US6041862A
(en)

1995-09-12
2000-03-28
Amerman; Thomas R.
Ground heat exchange system

US6276438B1
(en)

1995-09-12
2001-08-21
Thomas R. Amerman
Energy systems

US6250371B1
(en)

1995-09-12
2001-06-26
Enlink Geoenergy Services, Inc.
Energy transfer systems

NL1002506C2
(en)

1996-03-01
1997-09-03
Jan Van Turnhout

Heat or cold element.

US5669224A
(en)

1996-06-27
1997-09-23
Ontario Hydro
Direct expansion ground source heat pump

WO1999063282A1
(en)

1998-06-01
1999-12-09
Enlink Geoenergy Services, Inc.
Earth heat exchange system

JP2000241091A
(en)

1999-02-23
2000-09-08
Agency Of Ind Science & Technol
Heat accumulator

KR20010026171A
(en)

1999-09-03
2001-04-06
박호군
Absorption chiller using tubes with hydrophilic surface modification by plasma polymerization

JP3207843B1
(en)

2000-08-08
2001-09-10
株式会社日本触媒

Water-stopping agent paint, steel sheet pile for water-stopping method and water-stopping method using them

US7575043B2
(en)

2002-04-29
2009-08-18
Kauppila Richard W
Cooling arrangement for conveyors and other applications

WO2004105947A2
(en)

2003-05-23
2004-12-09
Bio-Rad Laboratories, Inc.
Localized temperature control for spatial arrays of reaction media

DE10342920B3
(en)

2003-09-15
2004-09-30
Germaat Polymer Gmbh
Collector for using earth’s temperature for heating/cooling, has collector line at level of lower third of foil trough/channel, filler consisting of material forming bearing layer

CN100413061C
(en)

2004-06-07
2008-08-20
鸿富锦精密工业（深圳）有限公司
Thermal tube and producing method thereof

US7698903B1
(en)

2006-04-24
2010-04-20
Global Green Building, Llc
Energy efficient ventilation system

US7617697B2
(en)

2006-05-16
2009-11-17
Mccaughan Michael
In-ground geothermal heat pump system

US20120000546A1
(en)

2006-12-05
2012-01-05
David Lewis
Systems and Methods for the Collection, Retention, and Redistribution of Rainwater and Methods of Construction of the Same

ES2308942B1
(en)

2008-04-04
2009-09-22
Edificios Sostenibles Getech,S.L

NEW MODEL OF SUSTAINABLE BUILDING.

US20100065243A1
(en)

2008-09-16
2010-03-18
Thomas Peyton A
Thermal capacitor for increasing energy efficiency

US9207021B2
(en)

2009-02-08
2015-12-08
Michael Gian
Geothermal air conditioning for electrical enclosure

US20100263824A1
(en)

2009-02-09
2010-10-21
Thomas Krueger
Geothermal Transfer System

DE102009033413A1
(en)

2009-07-16
2011-01-27
Geohumus International Research & Development Gmbh

Improvement of the heat transfer and the heat capacity of heat accumulators

AR081123A1
(en)

2009-07-23
2012-06-27
W & E Int Canada Corp

KITCHEN DEVICE THAT WORKS ON SOLAR POWER BASE

SE535370C2
(en)

2009-08-03
2012-07-10
Skanska Sverige Ab

Device and method for storing thermal energy

DE202009013639U1
(en)

2009-10-09
2011-03-03
Krecké, Edmond D., Dipl.-Ing.

Low energy building, especially self-sufficient zero energy house

US8991183B2
(en)

2010-07-12
2015-03-31
Siemens Aktiengesellschaft
Thermal energy storage and recovery device and system having a heat exchanger arrangement using a compressed gas

DK2561299T3
(en)

2010-07-12
2017-08-28
Siemens Ag

STORAGE AND RECOVERY OF HEAT ENERGY BASED ON THE PRINCIPLE PRINCIPLE OF TRANSPORT OF HEAT TRANSFER MEDIUM

US20120211195A1
(en)

2011-02-18
2012-08-23
Heise Lorne R
Control for Geothermal Heating System

JP2012255633A
(en)

2011-06-10
2012-12-27
Asahi Kasei Homes Co
Heat transfer filling material, underground heat exchange device, and filling method of heat transfer filling material

US9291372B2
(en)

2011-07-25
2016-03-22
Tai-Her Yang
Closed-loop temperature equalization device having a heat releasing device and multiple flowpaths

US9200850B2
(en)

2011-07-25
2015-12-01
Tai-Her Yang
Closed-loop temperature equalization device having a heat releasing system structured by multiple flowpaths

US20130025820A1
(en)

2011-07-25
2013-01-31
Tai-Her Yang
Close-loop temperature equalization device having single-flowpathheat releasing device

US20130042997A1
(en)

2011-08-15
2013-02-21
Tai-Her Yang
Open-loopnatural thermal energy releasing system wtih partialreflux

US9284952B2
(en)

2012-07-24
2016-03-15
Gary Scott Peele
Trench-conformable geothermal heat exchange reservoirs and related methods and systems

US9091460B2
(en)

2013-03-21
2015-07-28
Gtherm, Inc.
System and a method of operating a plurality of geothermal heat extraction borehole wells

US9593868B2
(en)

2015-02-20
2017-03-14
Vladimir Entin
Horizontal ground-coupled heat exchanger for geothermal systems

US11493238B2
(en)

2018-08-23
2022-11-08
Gary Scott Peele
Geothermal heat exchange reservoirs and related methods and systems

Family Cites Families (12)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

CH59350A
(en)

1912-02-13
1913-05-02
Heinrich Zoelly

Heating method

US2693939A
(en)

1949-05-06
1954-11-09
Marchant Lewis
Heating and cooling system

US2584573A
(en)

1950-01-31
1952-02-05
Frazer W Gay
Method and means for house heating

US2800456A
(en)

1953-08-10
1957-07-23
John C Shepherd
Refrigerant and process for making same

US2846421A
(en)

1954-02-18
1958-08-05
Phillips Petroleum Co
High heat capacity cooling medium

US3236294A
(en)

1961-11-09
1966-02-22
Harry E Thomason
Basementless solar home

US3130163A
(en)

1962-01-17
1964-04-21
Royal Super Ice Company
Refrigeration method

US3563304A
(en)

1969-01-28
1971-02-16
Carrier Corp
Reverse cycle refrigeration system utilizing latent heat storage

US3581513A
(en)

1969-04-23
1971-06-01
Inst Gas Technology
Method and system for freezing rock and soil

SU322084A1
(en)

1970-03-23
1973-10-26

DEVICE FOR EXTRACTION OF GEOTHERMAL ENERGY

US4010731A
(en)

1975-10-23
1977-03-08
Halm Instrument Co., Inc.
Heat storage tank

US4011736A
(en)

1975-11-12
1977-03-15
Halm Instrument Co., Inc.
Cold storage tank

1976

1976-08-27
US
US05/718,348
patent/US4042012A/en
not_active
Expired – Lifetime

1977

1977-05-26
US
US05/800,705
patent/US4142576A/en
not_active
Expired – Lifetime

1977-08-15
GB
GB34178/77A
patent/GB1569325A/en
not_active
Expired

1977-08-17
SE
SE7709259A
patent/SE7709259L/en
not_active
Application Discontinuation

1977-08-25
DE
DE19772738254
patent/DE2738254A1/en
active
Pending

1977-08-26
CA
CA285,574A
patent/CA1045394A/en
not_active
Expired

1977-08-26
FR
FR7726093A
patent/FR2363063A1/en
not_active
Withdrawn

1977-08-27
JP
JP10311077A
patent/JPS5348259A/en
active
Granted

Also Published As

Publication number
Publication date

DE2738254A1
(en)

1978-03-09

SE7709259L
(en)

1978-02-28

US4142576A
(en)

1979-03-06

CA1045394A
(en)

1979-01-02

FR2363063A1
(en)

1978-03-24

JPS5728867B2
(en)

1982-06-18

US4042012A
(en)

1977-08-16

JPS5348259A
(en)

1978-05-01

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