US20110154838A1 - Heat exchange system - Google Patents

Abstract

A modular heat exchange system having a refrigerant system for cycling a refrigerant through a compressor, a condenser, an expansion valve, and an evaporator, a heat source circulation system which circulates a heat exchange fluid between a heat source and the evaporator, a heat sink circulation system which circulates a heat absorption fluid between a heat sink and the condenser, a heat exchanger for exchanging thermal energy between one of the heat exchange fluid or the heat absorption fluid; and a neutral tank, wherein the one of the heat exchange fluid or the heat absorption fluid is deposited in the neutral tank upon returning from the heat exchanger.

Description

CROSS REFERENCE TO RELATED APPLICATION
• This is a Continuation-in-Part of application Ser. No. 12/752,585 filed Apr. 1, 2010, now pending, which is a Continuation-in-Part of application Ser. No. 12/543,268 filed Aug. 18, 2009, now pending. The disclosures of the prior applications are hereby incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• Aspects of the present invention relate to a portable and scalable heat exchange system. More particularly, aspects of the invention relate to a high-efficiency water-to-water heat exchange system for providing an efficient, portable, and/or scalable heating and/or cooling source.
• 2. Background of the Technology
• FIG. 1 shows an exemplary vapor-compression refrigeration cycle2 used in many heat exchange systems, in which a refrigerant is circulated through a closed-loop compression and expansion cycle. As shown inFIG. 1, the refrigerant begins as a vapor at point A. DuringPhase1 of the cycle, the refrigerant vapor is compressed and circulated by acompressor10, resulting in a high-pressure, high-temperature refrigerant vapor. The electro-mechanical energy of thecompressor10 is also converted into heat energy carried by the refrigerant vapor, which exits thecompressor10 as a superheated vapor. DuringPhase2 of the cycle, the superheated vapor passes through acondenser20 where a heat exchange process pulls heat energy from the superheated vapor, causing the refrigerant to condense into a high-pressure liquid. As shown atPhase3 of the cycle, the hot liquid refrigerant is then directed through athermal expansion valve30, which meters the flow of refrigerant to theevaporator40 and usually results in a flash lowering of the pressure and temperature of the condensed hot liquid refrigerant. As a result, the low-pressure, low-temperature liquid or saturated liquid/vapor refrigerant enters theevaporator40 duringPhase4 of the cycle, wherein a second heat exchange process draws heat energy from a heat source, such as water or air, to the refrigerant, causing the refrigerant to reach a saturation temperature and returning the refrigerant to the vapor state at point A. The cycle is repeated.
• In many conventional residential heat pump systems, for example, for supplying heat, theheat exchanging condenser20 extracts heat energy from the superheated refrigerant vapor duringPhase2 of the cycle by using ablower50 to direct cool air across condenser coils carrying the hot vapor (seeFIG. 1). The cool air conducts heat energy from the coils and the heated air is supplied by the blower through ducting, for example, to directly heat the home or residence. The evaporator, on the other hand, typically relies on the air temperature outside the home for drawing heat into the refrigerant duringPhase4 of the cycle.
• For supplying cool air, theblower50 may instead be used to direct hot air across evaporator coils carrying the cooler fluid refrigerant duringPhase4 of thecycle2. The cooler fluid refrigerant conducts heat energy from the hot air, and the resulting cooler air may be supplied to the home. Under such circumstances, thecondenser20 relies on the outside air to cool the superheated vapor duringPhase2 of the vapor-compression cycle2
• In some conventional systems, the heat pump may be designed with a reversible valve and specialized heat exchangers, for example, allowing the vapor-compression cycle2 to operate in either direction, with each heat exchanger serving as either a condenser or an evaporator. The cycle of the heat pump can thus be reversed, so that, depending on the desired climate, a single blower may be used to direct hot or cool air across coils, for example, carrying the cooler refrigerant fluid or the superheated refrigerant vapor, respectively.
• A typical air-source heat pump, as described above, works harder to transfer heat from a cooler place to a warmer place as the temperature difference increases between the cooler and warmer places. Accordingly, the performance of an air-source heat pump deteriorates significantly, for example, during the winter months in a very cold climate, as the temperature difference between the air outside a home becomes significantly less than the desired temperature inside the home.
• A ground source heat pump system, which typically extracts heat from the ground, or a body of water, may be used to counteract the effect of significant temperature gradients between the heat source and the heat sink. This is because the ground below a certain depth, and water below a certain level, maintains a fairly constant temperature year round, leading to generally lower temperature differentials throughout significant periods of the year, allowing for increased performance of the heat pump. As shown inFIG. 2, the vapor-compression cycle2 described inFIG. 1 may be coupled with aground source loop3 that carries a heat exchange fluid, such as water, for example. The heat exchange fluid conducts heat while flowing throughconduits4 buried in the ground or sunk under a body of water5. A portion of the heat carried by the heat exchange fluid in theconduits4 is transferred to the cooler liquid refrigerant by conduction through a heat exchange process performed by theevaporator40 duringPhase4 of the vapor-compression cycle2. The refrigerant is vaporized, and the refrigerant vapor is then compressed duringPhase1 of the vapor-compression cycle. As described previously, ablower50 may be used to direct cool air across condenser coils while carrying the hot vapor duringPhase2 of the vapor-compression cycle2 in order to provide heat to the interior of a structure. Additionally, aheat sink loop6 may be coupled with thecondenser20 to capture heat transferred from the heat exchange fluid duringPhase4 of the vapor-compression cycle2, along with heat that is added through the electro-mechanical energy input by thecompressor10 duringPhase1 of the vapor-compression cycle2, into aheat sink60, which could be a tank of hot water, for example. The condensed refrigerant exiting thecondenser20 is then expanded duringPhase3 of the vapor-compression cycle2 and the cooler refrigerant liquid enters theevaporator40 once again to draw more heat from the heat exchange fluid flowing through theground source loop3.
• A typical ground source system, such as theground source loop3 described above, is expensive to construct and can be extremely disruptive to install because thousands of feet of piping may need to be placed in horizontally dug trenches or wells dug vertically deep into the ground, to effectively tap into the thermal energy contained therein. And although the thermal conductivity of water is greater than that of the ground, generally allowing for less piping to be placed into a body of water, access to a body of water close enough to the home for the purpose of creating a ground source system is often unfeasible.
• There exists a need for a heat exchange system which combines the efficiencies of the thermal conductivity of a fluid, such as water and a specially tuned vapor-compression cycle to produce an efficient, portable, and scalable heat exchange system for simultaneously providing heating and/or cooling.
SUMMARY OF THE INVENTION
• Aspects of the present invention provide for a heat exchange system that combines a thermally conductive fluid and a specially tuned vapor-compression cycle in an extremely efficient, modular, portable, and scalable system for providing superior heat exchange capabilities for heating and/or cooling in almost any environment. As a result, the heat exchange system in accordance with aspects of the present invention may be disassembled and assembled with ease and without causing damage to the structural components of the system to permit convenient installation in residential, commercial and industrial settings. Aspects of the present invention include operation of the system using a portable generator, allowing deployment in remote locations, such as forward operating military outposts, or to provide heating, cooling, hot water and chilled water to people in need around the world, such as victims in disaster relief centers and in refugee camps.
• Aspects of the invention, and, in particular, the increased performance of the efficiently designed heat exchange system, including an automated fluid management system, permit enhanced heating and cooling while creating a significantly reduced footprint on the environment over conventional heating and cooling systems that rely on fossil fuels to function.
• Additional advantages and novel features of aspects of the invention will be set forth in part in the description that follows, and in part will become more apparent to those skilled in the art upon examination of the following or upon learning by practice of the invention.
BRIEF DESCRIPTION OF THE FIGURES
• FIG. 1 shows an exemplary vapor-compression cycle as typically used in heat exchange systems;
• FIG. 2 shows an exemplary ground source heat pump system as is known in the prior art;
• FIG. 3 shows a system flow diagram of a heat exchange system, in accordance with aspects of the present invention;
• FIG. 4 shows a perspective view of an exemplary heat exchange system, in accordance with aspects of the present invention;
• FIG. 5 shows an enlarged view of various components of the exemplary heat exchange unit, in accordance with aspects of the present invention;
• FIG. 6 shows a cutaway view of an exemplary heat sink, in accordance with aspects of the present invention;
• FIG. 7 is a system flow diagram of an exemplary heat exchange system with an integrated fluid management system; and
• FIG. 8 is a system flow diagram of an exemplary heat exchange system with an integrated fluid management system.
DETAILED DESCRIPTION
• FIG. 3 is an exemplary flow diagram in accordance with aspects of the present invention. Theheat exchange system100 comprises a vapor-compression refrigeration cycle having acompressor110, acondenser120, anexpansion valve130, and anevaporator140. Although many different refrigerants may be used, the refrigerant R-410A, a mixture of difluoromethane and pentafluoroethane, is preferred for its thermodynamic properties and because R-410A does not contribute to ozone depletion. As will be described in further detail, R-410A typically operates at higher pressures than most refrigerants, requiring increased strength in certain components of the system.
• As shown inFIGS. 3 and 4, aheat source200, such as a tank of water, may be provided to work in tandem with theheat exchange system100 to supply heat energy duringPhase4 of the vapor-compression cycle2. Theheat source200 may alternatively be a nearby lake or stream, for example. Theheat source200 may be connected to theheat exchange system100 through acirculation system210, which may be a closed-loop or open-loop system for circulating a heat exchange fluid, such as water. Thecirculation system210 may include apump215, for example, for circulating the heat exchange fluid from theheat source200, through theevaporator140 and back to theheat source200.Fluid flow valves216, such as ball or butterfly valves, may be installed on either side of thepump215, to allow for fluid flow to thepump215 to be shut off during assembly, or during repair and/or replacement of thepump215.Fluid flow conduits217 for carrying the heat exchange fluid205 through thecirculation system210 may include rigid and/or flexible tubing made of a thermally conductive material, such as copper or a modified polyethylene, for example. As shown inFIG. 4, thefluid flow conduits217 may include flexible tubing exterior to theheat exchange system100, copper or brass tubing, for example, inside of theheat exchange system100, and hard plastic tubing, for example, to form a coiled section of theevaporator140.
• As indicated by the longer arrows in the enlarged view ofFIG. 5, the heat exchange fluid205 is forced by thepump215 to flow through the stackedcoil section142 of theevaporator140 in a specified direction. The heat exchange function of theevaporator140 is accomplished by concurrently running a coldrefrigerant conduit132, which exits theexpansion valve130, through the stackedcoil section142 of theevaporator140. The coldrefrigerant conduit132 enters theevaporator140 at an evaporator entrance junction134 and exits the evaporator at anevaporator exit junction136. The coldrefrigerant conduit132 follows, and is contained within, the stackedcoil section142 of theevaporator140. The coldrefrigerant conduit132 is ideally situated to permit the entire outer surface area of the coldrefrigerant conduit132 to be in direct contact with the warmer heat exchange fluid205 flowing through the stackedcoil section142. Accordingly, increased thermal conduction from the heat exchange fluid duringPhase4 of the vapor-compression cycle2 is provided by the aforementioned arrangement of the structural components.
• As shown inFIG. 5, the refrigerant flow entering theevaporator140 has just completedPhase3 of the vapor-compression cycle, in which the hot refrigerant fluid has passed through theexpansion valve130 and experienced a rapid decrease in pressure and temperature. As shown with the smaller arrows inFIG. 5, the cooler refrigerant fluid flows through the coldrefrigerant conduit132 in the same direction as the warmer heat exchange fluid flows through the stackedcoil section142 of theevaporator140. The concurrent tubular flow creates a variable temperature gradient over the length of the stackedcoil section142, in which the refrigerant absorbs the heat energy of the heat exchange fluid at a greater rate nearer the evaporator entrance junction134 than towards theevaporator exit junction136. The coldrefrigerant conduit132 follows, and is contained within, the stackedcoil section142 of theevaporator140. The refrigerant and the heat exchange fluid both approach an equilibrium temperature as the fluids flow in parallel through the respective conduits in theevaporator140. The refrigerant has thus completedPhase4 of the vapor-compression cycle, and, as a vapor, is now ready to enter thecompressor110.
• As shown inFIGS. 3 and 4, thecompressor110, which may be a reciprocating or scroll compressor, for example, supplies the electro-mechanical energy to compress the vapor into a superheated vapor duringPhase1 of the vapor-compression cycle2. Aheat sink300, such as a tank of water, may be provided to work in tandem with theheat exchange system100 to store the amplified heat energy extracted from the heat exchange fluid duringPhase4 of the vapor-compression cycle2. Theheat sink300 may be connected to theheat exchange system100 through a heatsink circulation system310, which may be a closed-loop or open-loop system for circulating a heat absorption fluid305, such as water. The heatsink circulation system310 may include apump315, for example, for circulating the heat absorption fluid from theheat sink300, through thecondenser120 and back to theheat sink300.Fluid flow valves316, such as ball or butterfly valves, may be installed on either side of thepump315, to allow for fluid flow to be shut off to thepump315 during assembly, or during repair and/or replacement of thepump315.Fluid flow conduits317 for carrying the heat absorption fluid through the heatsink circulation system310 may include rigid and/or flexible tubing made of a thermally conductive material, such as copper or a modified polyethylene, for example. As shown inFIG. 4, thefluid flow conduits317 may include rigid copper tubing, for example, insulated to protect heat loss during circulation of the heat absorption fluid through the heatsink circulation system310.
• As indicated by the longer arrows in the enlarged view ofFIG. 5, the heat absorption fluid is forced by thepump315 to flow through the stackedcoil section122 of thecondenser120 in a specified or predetermined direction. The heat exchange function of theevaporator120 is accomplished by concurrently running a hotrefrigerant conduit112, which exits thecompressor110, through the stackedcoil section122 of thecondenser120. The hotrefrigerant conduit112 enters thecondenser120 at acondenser entrance junction114 and exits the condenser at acondenser exit junction116. The hotrefrigerant conduit112 follows, and is contained within, the stackedcoil section122 of thecondenser120. The hotrefrigerant conduit112 is ideally situated to permit the entire outer surface area of the hotrefrigerant conduit112 to be in direct contact with the cooler heat absorption fluid flowing through the stackedcoil section122 of thecondenser120. This enables increased thermal conduction from the superheated refrigerant vapor duringPhase2 of the vapor-compression cycle2.
• As shown inFIG. 5, the refrigerant flow entering thecondenser120 has just completedPhase1 of the vapor-compression cycle, in which the refrigerant vapor was compressed by thecompressor110 and experienced a rapid increase in temperature. As shown with the smaller arrows inFIG. 5, the superheated refrigerant vapor flows through the hotrefrigerant conduit112 in an opposite direction relative to the cooler heat absorption fluid flowing through the stackedcoil section122 of thecondenser120. The countercurrent tubular flow maintains a nearly constant temperature gradient over the length of the stackedcoil section122, in which heat is conducted from the superheated refrigerant vapor into the cooler heat absorption fluid at nearly the same rate near thecondenser entrance junction114 as at thecondenser exit junction116. Particularly with the use of water as the heat absorption fluid, for example, which has a relatively high thermal conductivity, the countercurrent flow in thecondenser120 allows efficient transfer of a substantial portion of the heat energy drawn from the heat exchange fluid, as well as the work energy input from thecompressor110, into theheat sink300.
• In accordance with aspects of the present invention, a second condenser (not shown) may be provided between thecondenser120 and theexpansion valve130. In this region of the refrigeration cycle, sometimes referred to as the sub cool region, the refrigerant may still retain a certain amount of thermal energy that was not transferred to the heat absorption fluid during the exchange process in thefirst condenser120. Accordingly, the second condenser may be provided to draw additional thermal energy from the refrigerant into a fluid that may be circulated back to theheat source200. The warm fluid may thus transfer the additional thermal energy back into theheat source200 for storage and further use as described above.
• The heat exchange system of the present invention draws on the thermal energy contained in theheat source200, which may be a tank of water at ambient temperature, for example, and by way of the vapor-compression cycle2, deposits the withdrawn thermal energy efficiently into theheat sink300, which may be another tank of water, for example. Theheat sink300 may thus reach temperatures of more than 150° F. As shown inFIG. 4, the hot water in theheat sink300 may be drawn and pumped throughpipes400 to a radiant heating system, for example, or a hydronic coil and blower arrangement that is connected to a ducting system, in order to provide a constant and efficient source of heat for the interior of a structure. In addition, a domestic hotwater storage tank500 may be connected to theheat sink300 to heat exchange thermal energy into the hotwater storage tank500 for potable water use.
• FIG. 6 shows an enlarged cutaway view of anexemplary heat sink300 in accordance with aspects of the present invention. Thefluid flow conduits317, which may be wrapped in insulating material to prevent the escape of thermal energy to the environment, may run from theheat sink300 to theheat exchange system100 and back to complete a closed loop, for example. Additionally, aheat exchange coil318, comprised of copper, or any other suitable material having high thermal conductivity, may be provided inside theheat sink300 to facilitate heat exchange from the hot water in thefluid flow conduits317 into theheat sink300. The hot water may then be drawn into thepipes400 to supply a radiant heating system, for example.
• As shown inFIG. 6, the domestic hotwater storage tank500 may connect to theheat sink300 bypipes502, which may be insulated, to conduct heat from the hot water in theheat sink300 by way of heat exchange coils504, also placed in theheat sink300. As such, the domestic hot water system may be completely separate from the heatsink circulation system310, the efficient heat exchange system thus providing the thermal energy for potable hot water use in a safe and cost-effective manner.
• As shown inFIGS. 3 and 4, in accordance with aspects of the present invention, an electronic control unit (ECU)540 may be provided to control operation of thecompressor110 and the circulation pumps215 and315. TheECU540 may operate with one or more thermostats, for example, to maintain the system in an efficient operating range. For instance, theECU540 may set thecompressor110 and the circulation pumps215 and315 to run if the temperature of the water in theheat sink300 drops below a certain efficiency threshold temperature, for example, or alternatively, if the temperature of the water in theheat source200 rises above a certain efficiency threshold temperature. In another aspect of the present invention, as shown inFIG. 3, athermal energy source220 may provide supplemental thermal energy to the heat source cycle when a temperature gauge in theheat source200 indicates to theECU540 that the temperature of theheat source200 has dropped below a predetermined efficiency threshold. Thethermal energy source220 may be any suitable source for heating the heat exchange fluid205, such as a conventional hot water heating element of a predetermined wattage, for example, placed within thefluid flow conduit217. Other exemplary thermal energy sources in accordance with aspects of the present invention may include the abundant heat sources in restaurants from which the thermal energy can be drawn upon and deposited, through heat exchangers, for example, into theheat source200. Using a hydronic coil, piping and pumps, for example, the heat retained in the elevator penthouses of buildings can be transferred into the heat source cycle. Any ready source of heat that can be practically transferred into theheat source200 may be used as thethermal energy source220, including “hot spots” found in swimming pools, drain pipes, transformer rooms, data centers, computer rooms, and the upper space in certain high-ceiling rooms, to name just a few. The techniques to capture and transfer the thermal energy from athermal energy source220 may typically include hydronic systems, but any suitable method of transferring thermal energy from a secondary source of heat to theheat source200 is contemplated herein.
• As shown inFIG. 4, in accordance with aspects of the present invention, theheat exchange system100 may be fitted with an electronicpressure control unit550. In combination with one ormore pressure transducers552, the electronicpressure control unit550 may be set up to monitor the sensed pressure at any point in the system, including the intake (suction) pressure and the discharge (head) pressure of thecompressor110. Accordingly, measurement of the evaporator pressure and/or the condenser pressure can provide valuable insight into the efficiency of the system and whether the refrigerant charge is too low or excessive, for example. As shown inFIGS. 3 and5, asight glass135 may also be used to aid in the inspection of the refrigerant charge level, as bubbles in the line generally indicate an undercharge. Thesight glass135 is preferably located on the high-pressure liquid side of thecompressor110. In another aspect of the present invention, as shown inFIG. 3, a filter drier137 may be installed in the refrigerant path, preferably on the high-pressure liquid side of thecompressor110, to adsorb unwanted moisture in the refrigerant cycle.
• According to aspects of the present invention, the refrigerant charge in the vapor-compression cycle2 may be precisely determined in accordance with a length of the refrigerant run and the desired characteristics of a well-balanced heat exchange system. The R-410A refrigerant charge may be intentionally set to a level that allows the system to continue to operate at maximum efficiency, while increasing the discharge temperature of the superheated vapor discharged from thecompressor110. The unexpected results of the present invention call for a substantially lower refrigerant charge than normal to achieve the desired results of an efficient heat transfer between theheat source200 and theheat sink300.
• The use of R-410A enhances the ability to increase the temperature on the discharge side of thecompressor110, but requires much higher pressures to operate compared to previously used refrigerants. For example, to achieve a condensing temperature value of 140°, an R-410 high-side pressure must approach 550 psi. In other words, for the heat absorption fluid running through thecondenser coil section122, which is generally maintained at a temperature of 140° or higher, to condense the superheated vapor of the refrigerant in theconduit116, the pressure on the condenser side of the heat exchanger must approach 550 psi or higher. By using ascroll compressor110 rated to handle 650 psi before disengaging, and using tubes and fittings rated to withstand the elevated temperatures and pressures of an R-410A charged system, theheat exchange system100 can handle the higher pressures required to produce the higher compressor discharge temperatures necessary to ensure heat exchange occurs in the condenser at temperatures above 140° F.
• As heat energy is transferred from theheat source200 to theheat sink300, the temperature of theheat source200 lowers. Depending on the heat load demand, and the size of the body of water, for example, that is serving as theheat source200, the temperature of theheat source200 may drop significantly. Due to the parallel, concurrent tubular flow design of theevaporator140, and the ability to generally maintain theheat source200 in an ambient environment, the liquid refrigerant typically draws enough latent heat to effectively boil the liquid refrigerant and deliver vapor with enough pressure to thecompressor110 to function highly efficiently. In fact, a slight lowering of the refrigerant charge so that the intake side pressure is slightly lowered, while still preventing liquid refrigerant from being delivered to thecompressor110, may slightly elevate the compression ratio of thecompressor110. The higher compression ratio in turn may transfer more compression energy to the refrigerant during compression resulting in an even higher discharge temperature so that the heat absorption fluid can be heated to even higher temperatures.
• Thecolder heat source200 may also be used as a cooling medium for chilling water or providing cool air by employing the same water-to-water or water-to-air heat transfer means discussed above with respect to the hot water side. For example, hydronic coils, which draw upon the cold water created in theheat source200, may be used in combination with a fan to blow hot air across the hydronic coils to produce cooler air for the air conditioning of a particular structure. Similarly, as in the case of a domestic hot water tank, a separate cold water heat exchange system and storage tank, for example, can provide chilled water for a variety of uses.
• Features in accordance with aspects of the present invention include configuring the components of theheat exchange system100 to be compact, modular and/or portable, for example. As shown inFIG. 4, ahousing unit600 may havemultiple shelves601 and602 for vertically stacking and/or creating compartments for the storage and mounting of the various components of theheat exchange system100, such as thecompressor110, thecondenser120, theexpansion valve130, and theevaporator140. Various quick install features may be included to enable the easy installation and/or disassembly of theheat source200 and/or theheat sink300, including hose bibs (not shown), for example, for quickly connecting/disconnecting thefluid flow conduits217 and317 to theheat exchange system100. Mounting brackets may be provided to allow for quick and efficient mounting of the various components, such as thecompressor110, thecondenser120, theevaporator140 and the circulation pumps215 and315. Rubber padding, insulation, panels, doors and/or a cover may be provided that permit easy assembly/disassembly and access to the interior components for maintenance, while reducing the vibration, sound and heat loss that may be generated during operation of theheat exchange system100. Thehousing unit600 may be provided with a surface for mounting an integrated electric panel. As such, the heat exchange system may be prewired and ground to the integrated electric panel to provide a single, efficient connection to an external power source. Light Emitting Diode (LED) panels may be mounted to the housing unit to provide visible operational feedback to an observer with respect to various aspects or components of theheat exchange system100.
• By maintaining the modularity and portability of theheat exchange system100, theunit100 may be transported to and employed easily in remote locations. A generator may be used for producing the electricity needed by thecompressor110 and the circulation pumps215 and315, and access to a water source may provide both aheat source200 and aheat sink300 for heating and cooling purposes.
• FIG. 7 depicts aspects of an exemplary fluid management system700 in accordance with the present invention that may be integrated with various aspects theheat exchange system100 to provide precision balance and control for efficiently managing the varying heating and cooling load demands for an enclosed structure, for example. Thehousing unit600 may house the primary components of thevapor compression cycle2, such as thecompressor110, thecondenser120, theexpansion valve130, theevaporator140, thepumps215 and315, and/or theECU540. The heatsource circulation system210 includes theheat source200, which may be a 225 gallon water tank, for example, connected to theevaporator140 in thehousing unit600 byfluid flow conduits217. The heatsink circulation system310 includes theheat sink300, which may be a 55 gallon water tank, for example, connected to thecondenser120 in thehousing unit600 byfluid flow conduits317. The heatsink circulation system310 may include asecondary heat sink350, which may be a 160 gallon water tank, for example, also connected to thecondenser120 in thehousing unit600. Threeway valves360 and365 may be provided to control the fluid flow between the primary and secondary heat sinks,300 and350 respectively. Thevalves360 and365 are controlled to operate in tandem so that when thevalve360 shuts off fluid flow in the direction of theheat sink300 and instead directs the fluid flow to thesecondary heat sink350, thevalve365 opens to receive the fluid flow from thesecondary heat sink350 and is closed to receiving fluid flow from theheat sink300. Similarly, when thevalve360 shuts off the fluid flow in the direction of thesecondary heat sink350 and instead directs the fluid flow to theheat sink300, thevalve365 opens to receive the fluid flow from theheat sink300 and is closed to receiving fluid flow from thesecondary heat sink350. In this manner, theheat exchange system100 may select either theheat sink300 or thesecondary heat sink350 into which to deposit the thermal energy drawn from theheat source200.
• The components of the fluid management system700, in conjunction with the components of theheat exchange system100, must be sized appropriately to achieve a symbiotic balance between the thermal mass of theheat sinks300 and350, any associated hot side heat exchange systems, the thermal mass of theheat source200, and any associated cold side heat exchange systems, while accommodating the varying heating and cooling load demands. Factors such as ambient outdoor temperatures during summer and winter months, construction materials used for building the structure, including insulation and windows, and the habits of inhabitants or tenants, for example, may have a large impact on the various system configurations used to calibrate the heat exchange system in response to the required heating and cooling load demands.
• As shown inFIG. 7, a heatsource temperature gauge230 may be provided to monitor a core temperature of theheat source200. Similarly, temperature gauges302 and352 may be provided to respectively monitor core temperatures of theheat sink300 and thesecondary heat sink350. The various temperature gauges230,302 and352 may communicate with theECU540 by a set of relay switches, or any suitable circuit devices, including wireless thermostats, for example.
• In this manner, the fluid management system700 operates in balanced synchronization with theheat exchange system100 by monitoring the core temperatures of theheat source200 and theheat sinks300 and350. For example, under normal temperate conditions, the temperature of theheat source200 may be maintained to have a core temperature reading between 45 and 60° F. by cycling theheat exchange system100 as required while theheat sink300 maintains a temperature of 140° F. However, during colder winter months in many areas, the increased draw of stored thermal energy from theheat source200 in order to keep theheat sink300 at a particular temperature, 140° F. for example, may drop the temperature of theheat source200 below a threshold temperature, impacting the efficiency of theheat exchange system100. In particular, the ability for the heat exchange process in theevaporator140 to function efficiently may be impacted. As such, the fluid management system700 may be set to signal theECU540 to turn on theheater220 when the heatsource temperature gauge230 reads a core temperature below 38° F., for example. Under these circumstances, theECU540 may be programmed, for example, to continue operation of theheat exchange system100 until theheater220 provides enough supplemental thermal energy to the fluid flow to raise the core temperature of theheat source200 to a preset threshold winter temperature, 45° F. for example.
• Another feature in accordance with aspects of the present system may be the inclusion of a supplementalsolar heating system800 to provide yet another source of thermal energy during peak heating demand, such as during the winter months and/or during times of peak hot water demand, for example. As shown inFIG. 7, the supplementalsolar heating system800 may be configured to operate in tandem with either theheat sink300 or theheat source200 through a heat exchange process in which solar thermal units convert solar energy into thermal heat energy that is supplied to the fluid flow of theheat exchange system100. Threeway valves810 and820 may be provided to control the fluid flow between thesolar heating system800 and either theheat sink300 or theheat source200, respectively. Thevalves810 and820 are controlled to operate in tandem so that when thevalve810 shuts off fluid flow in the direction of theheat sink300 and instead directs the fluid flow to theheat source200, thevalve820 opens to receive the fluid flow from theheat source200 and is closed to receiving fluid flow from theheat sink300. Similarly, when thevalve810 shuts off the fluid flow in the direction of theheat source200 and instead directs the fluid flow to theheat sink300, thevalve820 opens to receive the fluid flow from theheat sink300 and is closed to receiving fluid flow from theheat source200. In this manner, theheat exchange system100 may select either theheat sink300 or theheat source200 as the beneficiary of the thermal energy produced by the solar thermal units of the supplementalsolar heating system800.
• During peak summer months in many areas, for example, where the need for cool air may drive a peak demand on theheat exchange system100 for chilled water, the fluid management system700 may be programmed to maintain the core temperature of theheat source200 at a lower threshold summer temperature, 38° F. for example. Under these circumstances, the amount of thermal energy drawn from theheat source200 may raise the core temperature of theheat sink300 to levels too high for the condenser heat exchange process to function efficiently. To keep the condenser section operating at lower temperatures, the fluid management system700 may thus be controlled to open thevalve360 in the direction of thesecondary heat sink350 to direct fluid from thecondenser120 to the largersecondary heat sink350 rather than theheat sink300. Concurrently, the fluid management system700 is controlled to open thevalve365 to receive fluid from thesecondary heat sink350 rather than from theheat sink300. In this manner, thesecondary heat sink350 may serve as a large depository of excess thermal energy during peak cooling demand, allowing the system to maintain the core temperature of theheat source200 at a lower desirable temperature without distressing the efficiency of the system.
• Another feature in accordance with aspects of the present invention may include providing a further mechanism for drawing off excess thermal energy in the event that thesecondary heat sink350 also reaches a core temperature considered too elevated for the efficient operation of thecondenser120 of theheat exchange system100. A pipe or conduit may be provided so that fluid can be pumped from thesecondary heat sink350 to an area where a fan and/or hydronic coils may be used to transfer the excess energy to an ambient air environment external to the structure, for example.
• Another feature in accordance with aspects of the present invention may include providing a neutral tank to the configuration of theheat exchange system100. For example, as shown inFIG. 8, aneutral tank900 may be configured to operate in combination with the fluid management system700 to serve as a temperature buffer for theheat sinks300 and350 and theheat source200. Because many aspects of theheat exchange system100 and the fluid management system700 will function as described above, a majority of the structure and functional aspects of theheat exchange system100 and the fluid management system700 are not repeated here.
• The piping of theheat exchange system100 and fluid management system700 may be modified, for example, to accommodate the introduction of theneutral tank900. As shown inFIG. 8, theneutral tank900 may be configured to respectively segregate the fluid flow to theheat exchangers120 and140 from the fluid flow returning from the heat exchange system, such as a hydronic coil and air handling system, or other secondary heat exchangers, used to heat and/or cool an objective space. For example, the heatsource circulation system210 may be configured so that the heat exchange fluid is supplied to theevaporator140 from theneutral tank900, with the heat exchange fluid being returned from theevaporator140 directly to the cold tank. Similarly, the heatsink circulation system310 may be configured so that the heat absorption fluid is supplied to thecondenser120 from one of theheat sinks300,350 or theneutral tank900, or a combination of theheat sinks300,350 and theneutral tank900, and the heat absorption fluid is returned from thecondenser120 directly to theheat sink300 or350. Moreover, the heat exchange fluid returning from the hydronic coils, for example, that is used to heat or cool the objective space may be deposited directly into theneutral tank900. In this manner, both theheat sinks300,350 and theheat source200 may be spared from the influence of the reduced or elevated temperature of the fluid returning from the heat exchange process (e.g., hydronic coils and air handler) that resulted in the respective heating or cooling of the objective space.
• For example, during cool months, the temperature of the fluid supplied from the heat sink(s)300,350 to the hydronic coils is reduced through the heat exchange process in order to supply heat to the objective space. As a result, theneutral tank900 permits the cooler fluid returning from the hydronic coils to be deposited into theneutral tank900, rather than back into the heat sink(s)300,350. Similarly, during warmer months, the temperature of the fluid supplied from theheat source200 to the hydronic coils is elevated through the heat exchange process (e.g., hydronic coils and air handler) in order to cool the objective space. As a result, theneutral tank900 permits the warmer fluid to be deposited into theneutral tank900, rather than back into theheat source200. In this manner, theheat sinks300,350 and theheat source200 may deliver fluid at temperatures that have not been tempered by fluid returning from the heat exchange process used to heat or cool the objective space. Thus, the fluid delivered to the hydronic coils, for example, may be maintained at temperatures that are more effective for heating or cooling of the structure, while the temperatures of the fluids in theheat sinks300,350 andheat source200 may be more consistently controlled, enhancing the operation and efficiency of the system. Theneutral tank900 may thus buffer theheat sinks300,350 and theheat source200 from large fluctuations in temperatures that may be associated with peak system demand, for example. In turn, the operation and efficiency of theheat exchangers120 and140 may be effectively controlled due to the consistent maintenance of the temperatures of the heat exchange fluids supplied from theheat sinks300,350 and theheat source200. Although described above as a tank, theneutral tank900 may be any suitable receptacle for the storage and maintenance of a heat exchange medium in accordance with aspects of the present invention.
• While this invention has been described in conjunction with the exemplary aspects outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that are or may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the exemplary aspects of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention, including increasing the size of various components, including the heat source, the heat sinks, and/or the neutral tank, for example, to scale the system appropriately for different applications. Therefore, the invention is intended to embrace all known or later-developed alternatives, modifications, variations, improvements, and/or substantial equivalents.

Claims (18)

1. A modular heat exchange system comprising:

a refrigerant system which cycles a refrigerant through a compressor, a condenser, an expansion valve, and an evaporator;

a heat source circulation system which circulates a heat exchange fluid between a heat source and the evaporator;

a heat sink circulation system which circulates a heat absorption fluid between a heat sink and the condenser;

a heat exchanger for exchanging thermal energy between one of the heat exchange fluid or the heat absorption fluid; and

a neutral tank, wherein the one of the heat exchange fluid or the heat absorption fluid is deposited in the neutral tank upon returning from the heat exchanger.

2. The modular heat exchange system ofclaim 1, wherein the refrigerant is R-410A.

3. The modular heat exchange system ofclaim 1, wherein the heat exchange fluid is water.

4. The modular heat exchange system ofclaim 1, wherein the heat absorption fluid is water.

5. The modular heat exchange system ofclaim 1, wherein the heat source circulation system further comprises a fluid flow conduit connecting the heat source to the evaporator.

6. The modular heat exchange system ofclaim 1, wherein the heat exchanger comprises hydronic coils.

7. The modular heat exchange system ofclaim 1, wherein the heat source is a body of water.

8. The modular heat exchange system ofclaim 7, wherein the body of water is contained in a heat source storage tank.

9. The modular heat exchange system ofclaim 1, wherein the heat sink is a body of water contained in a heat sink storage tank.

10. The modular heat exchange system ofclaim 1, further comprising a thermal energy source, wherein thermal energy is transferred from the thermal energy source to the heat exchange fluid when the core temperature of the heat source falls below a threshold temperature while the core temperature of the heat sink is maintained at a constant temperature.

11. The modular heat exchange system ofclaim 10, wherein the heat absorption fluid is cycled through the solar energy thermal unit to maintain the core temperature of the heat sink.

12. The modular heat exchange system ofclaim 11, further comprising a first valve and a second valve, wherein the first valve and the second valve work in tandem to cycle only one of the heat exchange fluid and the heat absorption fluid through the solar energy thermal unit.

13. The modular heat exchange system ofclaim 1, wherein the heat sink is one of a primary heat sink or a secondary heat sink.

14. The modular heat exchange system ofclaim 13, further comprising a first sink valve and a second sink valve, wherein the first sink valve and the second sink valve work in tandem to cycle the heat absorption fluid to only one of the primary heat sink and the secondary heat sink.

15. The modular heat exchange system ofclaim 14, wherein the heat absorption fluid is cycled to the secondary heat sink when the core temperature in the primary heat sink determined by the second temperature gauge rises above a threshold temperature while the core temperature of the heat source determined by the first temperature gauge is maintained at a constant temperature.

16. The modular heat exchange system ofclaim 10, wherein the thermal energy source is a solar energy thermal unit.

17. The modular heat exchange system ofclaim 1, wherein the heat exchange fluid is supplied to the evaporator by the neutral tank.

18. The modular heat exchange system ofclaim 1, wherein the heat absorption fluid is supplied to the condenser by one of the neutral tank or the heat sink.

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