WO2010070372A2

WO2010070372A2 - Direct expansion earth coupled heat pump or refrigerant loop system

Info

Publication number: WO2010070372A2
Application number: PCT/IB2007/046668
Authority: WO
Inventors: Herbert Rittberger
Original assignee: Herbert Rittberger
Priority date: 2006-10-18
Filing date: 2007-10-18
Publication date: 2010-06-24
Also published as: WO2010070372A3; WO2010070372A4

Abstract

Direct expension earth coupled heat pump or refrigerent loop system has simplest technology with a lower installation cost and increased performance in efficiency without need of circulating pump for transfer media is required. The present system consists with 20 feet long and 11/8 inch diameters thermoeveporator outer and inner pipes (3 & 4), each thermo evaporator pipe consists with refrigerant and metering device or expansion device which is sealed in each pipe and together with indestructible copper and silver brazing. Each outer and inner pipe is made with refrigeration grade copper tube. Each thermo evaporator pipe is inserted in pre drilled vertical holes grouted and connected in parallel with insulated copper tubing. Check valve ball is closed into the heating mode loop system and open in cooling mode system. Liquid refrigerant is evaporate between outer and inner pipe into the heating mode loop system and outer pipe is contact with earth into the heating mode loop system.

Description

"DIRECT EXPANSION EARTH COUPLED HEAT PUMP OR REFRIGERANT LOOP SYSTEM"

FIELD OF THE INVENTION: -

The present invention relates to "DIRECT EXPANSION EARTH COUPLED HEAT PUMP OR REFRIGERANT LOOP SYSTEM" which provides simplest technology with a lower installation cost and increased performance in efficiency without need of circulating pump for transfer media is required.

BACKGROUND ART: -

Heat pumps have long been known and employed in the heating, ventilating, and air conditioning industry. By the stud}' of conventional technologies, which have confidences on the fact that the earth (beneath the surface) remains at a relatively constant temperature throughout the year, which offers a steady and incredibly large heat source for heating mode, heat sink for cooling mode and heat storage medium for thermal energetic uses. Direct expansion system similarly uses a ground coil system, In which the liquid/gaseous refrigerent is sent directly out into copper coils buried in the ground where refrigerent is vaporized or condensed with the earth.

Today a less frequently used technology is reffered to as direct expansion ground (earth) coupled heat pump system. Refrigerent lines are buried in the ground(earth) on either horizontal or vertical arrangement and thereby intermediate heat exchanger and fluid are eliminated. The conventional technology for a direct expansion earth coupled heat pump was one that had its refrigerant evaporator/condenser in direct thermal contact with the earth from which heat was either extracted from in the heating mode or is introduced to in the cooling mode of operation. Many attempts have been made in the past to develop successful DX (Direct Expansion) earth coupled heat pumps for residential and commercial uses, which are failed adequately to meet a number of requirements associated with an economically and functionally viable systems.

Some of the shortcomings are included with the conventional technology of Direct expansion earth - coupled system are described below:- a. Refrigerent management and oil return is impotant but inadequate oil return to the compressor primarily in the heating mode; inadequate evaporator length and spacing for properly extracting heat from the earth resulting in low capacity and low efficiency of the systems. b. Operating with too low a refrigerent temperature in winter can freeze the ground(earth) and reduce heat transfer. c. Lack of a proper means to store additional refrigerant is required during the cooling operation. d. Lack of volume control of the compressor for providing the necessary increase in displacement during the heating operation over that displacement needed for the cooling operation. This lack of displacement control resulted in insufficient heating capacity during the coldest weather. e. Operating with too high a refrigerent temperature in summer can bake the ground and reduce heat transfer. The conventional systems employ closed loops of soft copper tubing to directly transfer heat between the ground and the refrigerant. The thermal conductivity of copper is about 19 Btu/sq.ft-hr-oF per inch of wall thickness, whereas that of HDPE pipe is only 2.7 Btu/sq.ft-hr-oF per inch. The conventional DX ground loops can be installed in a horizontal trenched configuration or a Vertical U-tube configuration. Horizontal- loop DX systems require about 350 feet of copper tubing per system ton. Because of their shorter length, horizontal ground loops need only about 500 square feet of land area per system ton. Similarly, Vertical Direct Expansion (DX) systems require only a 3-inch diameter bores to a depth of 120 feet per ton. Vertical DX boreholes should be spaced at least 20 feet apart to minimize the possibility of ground freezing and buckling in the heating mode or excessive warming and drying of the soil in the cooling mode.

DESCRIPTION OF THE INVENTION: - The new present invention is to overcome the above drawbacks of the existing systems, marking the usage of Heat energy from the soil more safe and convenient, with simple ability to replace. This present invention is well suited for most soil condition and when minimum disruption of the landscaping is desired. The present invention; Direct Expansion earth coupled heat pump system circulates refrigerant, instead of water or antifreeze. The refrigerant is circulated in thermo evaporator piping buried in the ground, rather than plastic piping. These systems are potentially more efficient than water loop systems.

FIG. 1 represents a schematic diagram of a reverse cycle direct expansion earth coupled heat pump system, with the arrows indicating the direction of travel of the refrigerant through the system in the heating cycle.

FIG. 2 represents a schematic diagram of reverse cycle direct expansion earth coupled heat pump system, with the arrows indicating the direction of travel of the refrigerant with the system in the cooling mode.

Heating Mode

Schematic diagram of a reverse cycle direct expansion earth coupled heat pump system 1, with the arrows indicating the direction of travel of the refrigerant 7 through the system in the heating mode cycle is shown in Fig. 1. High Pressure liquid is entered from entrance of heat pump 1 into the indoor heat heat exchanger. High pressure liquid is pass fro the liquid line 2 under high pressure closes port "A" in brass body 5 to force refrigerent through capillary tube or expansion device 6 merering refrigerent out of port "B". Loquid refrigerent 7 evaporates between outer pipe 3 and inner pipe 4. Inner pipe 4 picks heat from the outer pipe 3 in contact with earth and turn to low pressure, after leaving thermal pipes (3 & 4). It will enter reversing valve in indoor unit from reversing valve to suction accumulator being sucked at compressor which will pump gas into high pressure and high temperature. Then the gas goes back over DHW Coil to reversing valve and to enter heat exchanger where temperature is released to circulating water to indoor water storage tank. Refrigerent 7 under high pressure gives up heat and turns to liquid returning via check valve ball 8 to outdoor geothermal pipes, repeating the cycle. By this way brass body 5 is consist with two different size pipes and separates two operations.

Cooling Mode

Schematic diagram of reverse cycle direct expansion earth coupled heat pump 1 system, with the arrows indicating the direction of travel of the refrigerant 7 with the system in the cooling mode is shown in Fig. 2. High Pressure hot gas from compressor goes over DHW coil to reversing valve. Different reversing valve cycle routes gas to geo-pipe. Discharge from compressor to cavity between inner pipe 4 and outer pipe 3. Heat will be given up to cavity between inner pipe 4 and outer pipe 3. Heat will be given upto outer pipe 3 in contact with earth earth in process, high pressure vapors turns to high pressure liquid, which will enter port "A" in brass body forcing liquid refrigerent through small inner pipe 2 to indoor unit where refrigerent 7 will enter thermo expansion valve to metering it into the heat exchanger where circulating water in separate opposed pipe gives heat (cool) to the gas, which will turn low pressure in process passing to reversing valve, suction accumulator and to compressor low side as super heated, low pressure, gas being compressed and discharges as high pressure gas repeating the cycle.

Brass body 5 in pipes contains check valve ball 8 and a attached capillary tubing 6 (or expansion device) O-ring seals 9 body to pipes, reducing chance of leakage through end cap 10 also double sealed with heat shrink pipe. Connecting lines from geo pipe to geo pipe are insulated and braised connections on each pipe are accessible through inspecting ports installed over pipes in ground.

In the present invented direct expansion system has no need to circulate any media or fluid through a loop or take water from a well. The device uses ground water source heat pump. Thermo evaporator pipes approximately 20 feet long and 11/8 inch diameter, each containing its own refrigerent flow and metering device, inserted in pre drilled vertical holes, grouted and connected in parralel with insulated copper tubing to specially designed Heat Pump, absorbs or reject heat to and from the ground, depending on soil condition. Each evaporator condenser absorbs up to 6000 BTU per pipe, makes it possible for up to 6 ton systems. The key factor results in a remarkably low energy cost since no circulating pump for transfer media is required. Thermo evaporator pipes are made with refrigeration grade copper, specifically engineered and manufactured expansion. The flow device is sealed in each pipe and together with indesructible copper and silver brazing; it should be a heat source for average house possible on an average lot even in existing; location with different Heat system, to be converted for Heat Pump. A Heat Pump System in which refrigerent is circulated in pipes buried underground is relatively new. A number of pipes at a length of 20 feet in diameter, installed in a borehole between 3 to 5 inches and grouted out with bentonite, are used for specific heat recovery, depeding on soil and ground condition, usually 2 pipes per ton. Spacing between pipes should be about 15 feet and be kept away from foundations and buildings, at least 6 feet. Heat pumps are manufactured in 2 Series: Direct to air or Direct to water, in series to 6 tons. Each Heat puimp is equipped with Scroll Compressor, suction accumulator , TX Valve and receiver with check valve.

The advantages of the present invention have higher efficiency with less ground space. The present invention does not require any pumps or water or antifreeze.

Claims

I claim

1. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM consists with 20 feet long and 11/8 inch diameters thermoevaporator outer and inner pipes (3 & 4);

each thermo evaporator pipe consists with refrigerent 7 and metering device or expansion device 6 which is sealed in each pipe and together with indestructible copper and silver brazing.

2. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or

REFRIGERENT LOOP SYSTEM as claimed in claim 1, wherein each outer and inner pipe (3 & 4) are made with refrigeration grade copper tube.

3. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or

REFRIGERENT LOOP SYSTEM as claimed in claim 1, wherein each thermo evaporator pipe are inserted in predrilled vertical holes, grouted and connected in parallel with insulated copper tubing.

4. DIRECT EXPANMSION EABLTH COUPLED HEAT PUMP or

REFRIGERENT LOOP SYSTEM as claimed in claim 1 wherein, the heating mode loop system liquid refrigerent 7 from the heat exchanger enters liquid line 2 under high pressure.

5. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or

REFRIGERENT LOOP SYSTEM as claimed in claim 4 wherein check valve ball 8 is closed into the heating mode loop system.

6. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 4 wherein brass body 5 to force ferigerent through capillary tube expansion device 6 into the heating mode loop system.

7. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 4 wherein liquid refrigerent 7 is evaporate between outer and inner pipe (3 & 4) into the heating mode loop system,

8. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 4 wherein the outer pipe 3 is contact with earth into the heating mode loop system.

9. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 4 wherein liquid refπgerent 7 is entered reversing valve in indoor unit from reversing valve to suction accumulator to suck at compressor.

10. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 4 wherein into the heating mode loop system high pressure and high temperature gas goes back over DHW coil.

11. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 1 wherein check valve ball 8 is open into the cooling mode loop system.

12. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 1 wherein brass body in pipes contains check valve ball 8, an attached capillary tubing O- ring seals 9 body to pipes, end cap 10 and doubled sealed with heat shrink pipe.

13. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 1 wherin connecting lines form geo-pipe to geo-pipe are insulated.

14. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or REFRIGERENT LOOP SYSTEM as claimed in claim 1 wherein braised connection on each pipe are accessible through inspecting ports installed over pipes in ground.

15. DIRECT EXPANMSION EARTH COUPLED HEAT PUMP or

REFRIGERENT LOOP SYSTEM substantially as herein described with reference to the foregoing description and the accompanying drawings.