US20100236266A1

US20100236266A1 - Geothermal Heating and Cooling System

Info

Publication number: US20100236266A1
Application number: US12/409,445
Authority: US
Inventors: Michael Skidmore; Thomas W. Ferguson; Gregory Veith; Kacey Cahill
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-03-23
Filing date: 2009-03-23
Publication date: 2010-09-23

Abstract

A closed loop geothermal heat exchange system for providing energy efficient cooling during the warmer seasons and baseline heating during the colder season that in one preferred embodiment is comprised of a heat exchanger unit, a circulating pump and a connection to a community water supply by means of upstream and down stream piping. The up stream supply pipe is connected to the community water supply on the system side of the water metering device. Water would flow from the supply side connection by means of water main system pressure to the input side of a heat exchanger through a turbulence-inducing fixture or fixtures that would increase the thermal transfer between the heat exchanger and the water. The output side of the exchanger is connected to the input side of a small booster pump, which supplies additional pressure to the return pipe which may also be configured into a venturi to assist the return water flow and is connected to community water system downstream from the supply connection.

Description

FIELD OF THE INVENTION

The present invention relates in general to heating and cooling systems and in particular to geothermal heating and cooling systems also known as geo-exchange or ground source heat pumps. Ground source heating and cooling is a high-comfort, cost-effective, and environmentally friendly technology that takes advantage of the Earth's capacity to store energy.
The Earth's capacity to store energy from the sun and other geological activity results in a vast reservoir of renewable thermal energy estimated to exceed all other energy sources combined by more than two thousand times and is constantly renewed by the sun's energy.
At depths below 8 to 10 feet (2.5 to 3 meters), the earth's temperature remains around 50 to 60 degrees Fahrenheit all year round. During winter seasons, a geothermal system uses ground source heat pumps to collect this low-grade thermal energy from the earth and concentrates it inside the house or building to provide space heating. Conversely, during summer seasons the ground source heat pump draws heat from the building and returns it to the earth to provide space cooling. Ground source heat pumps use one of three general configurations to perform their heating and cooling function.
Open loop
Closed vertical loop.
Closed horizontal loop.
In an open loop system a thermal transfer fluid, usually water, is drawn into the heat exchanger and then discharged back to the source. The open loop system is an efficient and economical cooling system. Open loops take water in from an open source of water such as a pond, lake, river, or stream, circulate it through the heat exchanger system located within the dwelling and return it to the source
A typical design for a closed vertical loop system consist of a pipe that is inserted into the ground by drilling deeply into the earth and placing 400 to 600 feet of pipe in a vertical array. The thermal exchange fluid in the vertical loop is constantly circulated to and from the ground source and heat exchanger unit by a small pump. The fluid in the piping is often a mixture of water and glycol or other antifreeze type solutions. The vertical loop is by design more efficient for heating than cooling because the deeper one drills into the earth, the surrounding earth strata becomes warmer. While the vertical loop system is highly efficient and economical to operate, it requires an expensive infrastructure cost/investment that has prevented it from being utilized to the fullest capacity.
The closed horizontal loop functions in a manner similar to the vertical loop but are often laid out in a matrix rather then a straight loop. The horizontal loop design is most often used in a rural setting where the homeowner has sufficient land to accommodate the piping.
The underutilization of geothermal heating and cooling can be traced to the cost of installing infrastructure [the pipes essential for proper functioning], which can run $20,000.00 or higher depending on the type of system chosen.

PRIOR ART

The following is a summary of relevant geothermal patents.
Jansen: et al Patent application number 2004/0108096
A geothermal heating and cooling system that provides space conditioning by transferring heat or cooling from a city main water supply or other water source.
Jansen describes a method of eliminating the ground loop heat transfer mechanism by using a city water main for thermal transfer. The preferred embodiment of the Jansen system comprises a compressor means, a refrigerant liquid, and a conduit in which the refrigerant fluid travels coiled around a vaulted section of pipe which becomes part of the water main allowing the potable water to pass through the inner pipe. The weakness of Jansen is the necessity of cutting and inserting the vaulted section of pipe into the municipal main and the close proximity of refrigerant fluid and potable water and the potential for contamination of the potable water system. Widespread use of the Jansen system in an urban area would require numerous modifications to the main, thereby increasing the infrastructure cost and the probability of a system failure and contamination.
Yamamoto et al: U.S. Pat. No. 5,666,814
The Yamamoto device is an attempt to balance heat exchange between a condenser section and an evaporator section where water may be used to increase the efficiency of the thermal exchange and may be a geothermal source
Bardenheier et al: U.S. Pat. No. 4,782,888
The Bardenheier device describes a system of interconnecting a plurality of heat sources and sinks in an attempt to balance the transfer of thermal energy in such a way as to meter and charge for such transfer. The system uses a compressor based isolated primary heat transfer liquid such as Freon or other refrigerant at each individual source or sink and a secondary heat sink liquid such as a municipal water system to cool the primary thermal liquid.
Lawrence et al: (DeMarco device) U.S. Pat. No. 4,538,418
Lawrence et. al. describes the use of a duel heat exchanger pump configuration that uses in one configuration a municipal water system as a heat sink. The Lawrence device is similar to the Bardenheier device in that it uses a compressor/refrigerant-based system as the primary thermal transfer unit.
Biancardi et al: U.S. Pat. No. 5,878,588
The Biancardi device is based on the use of tap water to cool and dehumidify an area with elevated temperature and humidity. The weakness of the Biancardi device is that it is consumption based. The terminal point of the cooling tap water is the building's hot water heater that has a limited fill capacity.
Ace et al: U.S. Pat. No. 6,688,129
Ace states that a potable water system can be effectively used as a geothermal heat sink when coupled with a heat pump.
Holman et al: U.S. Pat. No. 4,176,788
Holman proposes a comprehensive geothermal structure that uses potable water consumption as an efficiency amplifier
Harrison et al: 2007/0235022A1
Harrison uses a two-loop system where one side is a source and the other side is a sink, where the sink side of the exchanger may be a potable water source, which uses passive backfilling to control sediment deposits.
DeMarco et al: U.S. Pat. No. 6,604,376
DeMarco is a continuation of the Lawrence patent with the addition of treated wastewater as a geothermal heat sink.
Other patents considered relevant and included by reference are:


	Yuan	4,409,798
	Herbert	4,599,870
	Worf	4,408,596
	Hochstrasser	4,301,320
	Gatling	4,495,781
	Ohmi	7,000,419
	Piao	6,629,427
	Jones	4,215,551
	Harnish	4,558,818
	Thoren	4,184,856

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A better understanding can be had with reference to detailed description of preferred embodiments and with reference to appended drawings. The embodiments presented are particular ways to realize the inventions benefits and are not inclusive of all ways possible. Therefore, there may exist embodiments that do not deviate from the spirit and scope of this disclosure as set forth by appended claims, but do not appear here as specific examples. It will be appreciated that a great plurality of alternative versions are possible. An object of this invention is to provide a low cost and less invasive alternative to traditional geothermal systems and the systems described as prior art The heart of all closed loop geothermal systems is the thermal transfer fluid usually comprised of a glycol water mixture circulating in the pipes. As mentioned above, the most significant factor that has prevented the widespread adoption of geothermal systems has been the excavation and installation of the pipes through which the thermal transfer fluid circulates.
One preferred embodiment of this system is comprised of water to air heat exchanger unit, a circulating pump and a connection to a community water supply, which remains at a relatively constant temperature, by means of upstream and down stream piping. The up stream pipe would be comprised of a connection to the community water supply on either side of the water metering device. A short tube connected to the intake side of a pump will be located inside the subject building. This pump will supply pressurized water to the intake side of a heat exchanger that is connected to a building's air circulating system as indicated in FIG. 1, and thereby circulate the cooler air throughout the building during the warmer months and warmer air during the colder months.
Conversely, the return side of the heat exchanger is connected to the inlet side of the return piping that is connected to the community water supply downstream from the supply piping on either side of the water metering device. Such an embodiment would be a neutral water consumption apparatus, an energy efficient cooling apparatus, and environmentally friendly.
Based on the number of geothermal systems in use, it is clear that the high cost, space consuming, and invasive techniques of the traditional geothermal systems has prevented full utilization of geothermal heating and cooling. It is also apparent as noted by the U.S Department of Energy that a geothermal system is an environmentally friendly and energy efficient means of heating and cooling. This invention provides low cost and minimally invasive access to geothermal heating and cooling by utilizing the extensive water transport infrastructure that already exist in most community and county water systems. The water conserving, energy efficient, and low cost characteristics of our invention make it an ideal solution to energy consumption problems in heavy electrical consumption areas like southern California which suffers rolling brown outs and electricity shortages.
Global warming is now at the forefront of the major problems facing the human race. While the exact cause of global warming can be debated, many scientists have concluded that human activity maybe a primary cause of the warming. They conclude that energy production and consumption based on burning fossil fuels has contributed a significant amount of the green house gases that trap heat in the atmosphere. The energy efficient characteristics of the present invention will decrease demand for electricity and subsequently the demand to burn fossil fuels.
Regardless of the outcome of global warming debates, the mortality of elderly people as a consequence of warm and cold weather cannot be debated. Every summer in the United States, we learn of numerous heat related deaths suffered by elderly residents. These people are often poor, already ill and cannot survive without adequate air conditioning. During the winter months they suffer from inadequate heating. It has always been the consensus that low cost geothermal heating and cooling was unworkable in an urban environment because of the space requirement of the ground loop piping. As this invention uses space already fitted with ground loop piping, this problem is resolved. The low cost, energy efficient, non-polluting nature of this invention can save lives, reduce pollution by reducing the need for usable energy generated by fossil fuels, and provide a workable geothermal heating and cooling solution in more densely populated areas.
Utilization of existing municipal water systems solves the problem of space demand of geothermal systems urban and municipal water supplied rural environment without consuming water. It is therefore appropriate for every area of the world including the semi arid regions. A municipal water circulating system can also provide minimal heating without the use of fossil full combustion heating units. A small pump circulating municipal water through a closed loop heat exchanger could save the lives of the poor, elderly, and ill without the economic resources to purchase and consume fossil fuels. A municipal water system supplied heat exchanger can also be used to preheat or pre-cool air passing over the condensing coil of a conventional heat pump, thereby significantly reducing its energy consumption during summer air conditioning and winter heating.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention can be better understood and is described in greater detail by reference to and in connection with the accompanying drawings.

FIG. #

1 is a functional diagram of one of the preferred embodiments of the present invention.

FIG. #

2 is a functional block diagram of another preferred embodiment wherein our basic system is coupled with a traditional heat pump system for the purpose of preheating air during the colder months and pre cooling the air during the warmer months.

FIG. #

3 is a functional diagram of a preferred embodiment of a purity confirmation module.

DETAILED DESCRIPTION OF THE INVENTION

In one preferred embodiment of this invention a municipal water system # 1 is used as the geothermal exchange source.
The upstream supply tap is on the system side of the buildings water meter # 2. Cool water from the underground municipal water pipes will flow around the water meter # 2 through a flow control valve # 3 that can in the event of contamination, system maintenance, or breech of the structural integrity be automatically or manually closed or the flow can be diverted to dwelling use or to the sanitary system. During normal operation of the system water would flow to the input side of the heat exchanger unit # 4. In some geographical areas, a turbulence-inducing insert # 8 will be used to increase the thermal transfer efficiency of the municipal water flow. The system fan will draw in the warmer air from the dwelling or the outside air; pass it over and between the heat exchanger pipes through which the cooler water is flowing. Cooler air will then pass into the dwelling ductwork cooling and dehumidifying the dwelling. The cool water will pass out of the heat exchanger through another flow control valve # 5 that will act as another safety control device that will in the event of maintenance, contamination or structural failure either automatically or manually shut off the flow or divert it to the sanitary system. Water will then flow into a purity confirmation module # 6 that will perform testing on a continuous basis. If a failure of any test is detected, the purity confirmation module will output a signal to the system PLC causing closure the flow control valve(s) and either stop water flow or divert any water flow to the sanitary system. The purity confirmation module may be comprised of one or more of (a broadband infrared laser source, a transmission mechanism and chamber where the light source will be transmitted through the water flow, a detector capable of measuring changes in transmitted signal strength associated with the presence of organic or biologic contaminants, a galvanic sensor capable of detecting changes in conductivity associated with anionic/cationic contaminants, a detector capable of measuring pH associated with changes in acidity or alkalinity, a coherent or broad spectrum light source capable of measuring changes in turbidity, and a control circuit capable of generating an output to the system PLC. In one preferred embodiment the broadband laser source would be comprised of multiple and differing infrared light emitting diodes with optical output wavelengths spanning 2000 nm to 5000 nm in the infrared spectrum. Most organic compounds and biologics will absorb infrared light at various wavelengths in this region of the electromagnetic spectrum. In one preferred embodiment the infrared optical path through the water stream would be lengthened by providing multiple infrared reflective surfaces in the transmission chamber. This increased optical path would serve to increase the modules sensitivity to small levels of organic and biologic contaminants. In another preferred embodiment the purity confirmation module will divert some portion of the water flow through a chamber equipped with UV treatment of the water. This water would be measured for conductivity with galvanic sensor measurements before and after the ultraviolet treatment, and a comparator circuit that reads and compares the output of the two galvanic sensor measurements. The measurement difference is compared to a preset value and if acceptable, the water will flow into the inlet side of a small booster pump # 7 that will provide a sufficient increase in flow pressure to inject the water back into the municipal water system through a return pipe which will be located downstream from the supply side pipe. In one preferred embodiment the thermal energy transferred to and from the heat exchanger is maximized via the use of a turbulence inducing insert(s) in the heat exchanger fluid transfer lines. This insert or inserts would insure elimination of laminar flow. Uniform or laminar flow of water in the tubes of the heat exchanger, results in insulating a portion of the thermal transfer media (in this case water) passing through the heat exchanger from the heat exchanger walls. This insulation effect reduces the heat exchangers efficiency. Turbulence inducing inserts would create random eddies, vortices, and other flow fluctuations which result in improved thermal transfer efficiency. In addition to improving the heat exchangers thermal transfer efficiency in lower flow rate applications, the turbulence inducing insert(s) would significantly expand the range of flow rates that could be used with a single heat exchanger design, thereby reducing system design complexity and ultimately system cost. In another preferred embodiment the 1st preferred embodiment would be coupled with a traditional heat pump # 9 and separate heat exchanger/blower # 10 to provide baseline warm air to the heat pump to heat the dwelling during the colder months. For example during the month of December that average temperature in the Midwest US is significantly colder then the average ground water temperature. Air drawn into the heat pump through the geothermal system would be warmed by the higher temperature of the community water system thereby making heating of a dwelling more energy efficient. In either of the preferred embodiments an in ground heat exchanger may be inserted between the pump and the community water return to assist in normalizing the temperature of the water being returned to the water main.
In another preferred embodiment the geothermal system herein described can either be installed inside the building or outside the building. The configuration of the apparatus will vary with the choice of location. When the unit is located within the structure, the water will be conveyed by a piping means to the unit where it will function as a heat exchange medium. The air circulating aspect will occur within the structure. When the unit is located outside the structure the heat exchange process can be secured by a variety of means such as a locked above ground enclosure or a subterranean vault like structure accessible only by the owner of the water supply.
One of the outside variations would have an above ground air intake means. In this embodiment, only air would be transported to the structure through under ground means reducing or eliminating the risk of deliberate or accidental contamination.
One of the outside variations would have ducting to draw intake air from the structure and ducting to return heated or cooled air to the structure. In one or more variations the inherent water system pressure is used to power a water turbine that can be used to turn the fan that moves the system heating or cooling air. Using water pressure to turn the system fan would permit minimal heating and cooling during a power outage. This could potentially protect the fragile elderly or sick during extreme weather or power outages as long as water system pressure exists.
It is therefore to be understood that various modifications and changes may be made in the specific methods, means, and apparatus of the invention as herein described, as well as it's described intended application and use without departing from the spirit and scope of the present invention as defined by the following claims:

Claims

1. A energy efficient, cost effective, and safe geothermal heating and cooling system for homes and buildings that uses the public water system in place of a dedicated energy transfer loop, uses the water in the public water system as the thermal transfer fluid, and can be integrated with existing systems to significantly improve their operating efficiencies.

2. A geothermal apparatus comprising a water source, a water transport means, a directional flow control valve whereby said water source is adaptively coupled to an air to water heat exchanger unit; said heat exchanger unit comprising a water inlet, a water outlet, a return means comprising a pumping means, a transport means, and a directional flow control valve, whereby the water is returned to the source.

3. A geothermal apparatus as claimed in claim 2 wherein said heat exchanger unit additionally includes a turbulence inducing insert or inserts.

4. The apparatus as claimed in claim 2 wherein the water source is a public water system.

5. The apparatus as claimed in claim 2 wherein the water source is any open water source such as a well, river, stream, or lake.

6. A method to circulate air throughout a structure including an air intake means, a geothermal heating and cooling means, an air circulating system; whereby said air circulating means is an enclosed fan coupled to the structure's heating, ventilating, and air conditioning system, said fan can be either a single stage or multi stage.

7. A geothermal apparatus safety device comprising an arrangement of flow control valves which in the event of contamination or mechanical failure will shut off or divert water flow away from the source.

8. A geothermal apparatus purity confirmation module comprising one or more of a tuned laser beam, an optical conduit, a coated durable glass surface, an output beam, a galvanic sensor means to detect the presence of anionic/cationic chemical contamination, a pH meter to detect any change in acidity or alkalinity, a laser or broad spectrum light source and sensor to detect changes in the turbidity of the water stream, and the means to compare changes in differences between the input signal and the output signal.

9. A geothermal apparatus as claimed in claim 8 where changes in the input and output signals that fall outside the pre-determined parameters and indicating an equipment failure or water contamination will activate the valve closure sequence.

10. A geothermal apparatus purity confirmation module as claimed in claim 8 comprising a galvanic sensor means to detect the presence of chemical contamination.

11. A geothermal apparatus purity confirmation module as claimed in claim 8 comprising an ultraviolet purification treatment of a portion of the water flow with galvanic sensor measurements before and after the ultraviolet treatment

12. A geothermal apparatus as claimed in claim 8 comprising a comparator circuit, that reads and compares the output of the two galvanic sensor measurements too a preset standard purity number and activates the valve closure/bypass sequence whenever a reading falls outside the predetermined standards.