Heat pump system

HEAT PUMP SYSTEM

Priority

This application takes priority from US provisional Patent Applications 61/087,467, filed Aug. 8, 2008, attorney docket Koh 1 Prov; and 61/103,311, filed Oct. 7, 2008, attorney docket Koh 2 Prov by David KOH. The disclosures of those applications are incorporated herein by reference.

Background of Invention

1. The present invention relates to a heat pump for and cooling and or heating.

2. Heat pumps have been particularly useful for refrigeration and for air conditioning and heating.

US Patent 3,071,935 to Kapeker refers to an automatic refrigeration and defrost system which uses an additional heat exchanger within the system in the order to improve efficiency of the system.

A United States Patent Application by Han, published as 20060196225, refers to the use of heat exchangers in a refrigeration cycle.

Brief summary of the Invention

The present invention includes a heat exchanger having an improved flow within for greater heat transfer efficiency.

The present invention improves efficiency by placing a heat exchanger between an output line and a suction line of a heat pump system.

The present invention also may include an electronic suction pressure control which optimizes the suction line temperature, and thereby limits pressure on the suction line.

Brief Description of the Drawings

Fig. 1 is a block diagram a refrigeration system embodiment of the present invention.

Fig. 2 is a block diagram another embodiment the refrigeration system of the present invention.

Fig. 3 is a flow diagram in the nature of a simplified elevation in section of an improved heat

Koh 3 PCT Specification Page 1 August 8, 2009 (1 :26am) exchanger of the present invention.

Fig. 4 is a flow diagram in the nature of a simplified elevation in section of an improved but less expensive embodiment of a heat exchanger.

Fig. 5 is a block diagram another embodiment the refrigeration system which optimizes suction line temperature.

Fig. 6 is a block diagram another embodiment the refrigeration system which optimizes suction line temperature.

Fig. 7 is an elevation in section of the Peltier thermocouple device shown twice in fig. 6, which optimizes suction line temperature.

Fig. 8 is a block diagram of the present invention in heating mode.

Fig. 9 is a block diagram of the present invention in air-conditioning mode.

Detailed Description of the Drawings Present Invention

Fig 1 illustrates an embodiment of the invention, installed in s system for cooling a refrigeration case, such as in a retail food store. Inserted into a conventional suction line 100 coming from a refrigeration case 100, is a Heat Exchanger 102, of the present invention, which raises the temperature and the vapor ratio in the suction line. This relieves strain on compressor 106, which strain would occur from trying to compress incompressible liquid. The less liquid, the less compressor load, and the less power consumption by compressor 106.

Compressor 106 outputs through line 108 through three alternative heat absorbers: Hot water tank 110 supplies hot water to the building. In winter, Heat reclaimer 111 heats the building. Any heat not so absorbed is sent to outside condenser 112 for dissipation outdoors.

Koh 3 PCT Specification Page 2 August 8, 2009 (1 :26am) Receiver tank 114 receives the outflow of those heat absorbers 110-112. From receiver tank 114, mostly liquid refrigerant at 75 to 90 degrees F is output at pipe 116 towards the refrigeration case [not shown] to cool the case. But, in the present invention, diverter valve 118 maybe closed to send refrigerant through heat exchanger 102, to be further cooled, and to heat refrigerant that is output through output 104, to make the fluid more vapor and less liquid, to relieve strain on compressor 106, which strain would occur from trying to compress incompressible liquid.

For convenience, valves 119 and 120 may be used with the diverter valve 118, for testing, bypass, and repair purposes. If an operator opens valve 118 to bypass the heat exchanger 102, the operator should close valves 119 & 120; and visa- versa. The system will be more efficient with valve 118 closed, and valves 119 & 120 open.

Fig 2 shows a similar arrangement as Fig. 1, but where heat exchanger 102 is mounted in output line 116 towards the refrigeration case, rather than in suction line 100 & 104. But the flow, through valve 119, around closed bypass valve 138, through heat exchanger 102, and through valve 120, also results in a similar flow pattern to Fig. 1. Thus heat transfer between output line 116 and suction line 104 may be similar between figs 1& 2. This again relieves strain on compressor 106, which strain would occur from trying to compress incompressible liquid.

Valves 138, 119, 120, 140, and 142 allow heat exchanger 102 to be bypassed.

Fig. 3 shows an improved heat exchanger 102 of the present invention. Fluid such as R-22 refrigerant from, in fig. 1, the refrigeration case, flows through inlet 200, Figs 1 & 3, through manifold 202 (fig. 3), through a plurality of distribution holes, such as 205-206. The presently preferred embodiment has from sixteen to twenty such holes 205-206. Fluid flows from the holes through a corresponding number of sealed large-diameter tubes 107-208. As the fluid passes through tubes 207-8 some heat transfers between chamber 210 and the large diameter tubes such as 207-208. Hot compressor output fluid from line 116 enters through inlet 212 into hot liquid filled middle chamber 214, where heat is transferred to large diameter tubes

Koh 3 PCT Specification Page 3 August 8, 2009 (1 :26am) 207-207 and small diameter tubes 220-222.

Fluid in tubes 207-208 passes through chamber 230, where more heat is transferred through the tube walls into the tubes 207-8, which then turn 180 degrees back, to flow towards middle chamber 214, through middle chamber 214, transferring more heat from middle chamber 214 to tubes 207-208. the fluid discharges from tubes 207-208 through outlets 247-248 into chamber 210. Fluid then flows through chamber 210, warming tubes 207-208, out through about forty smaller diameter tubes such as 220-222, wherein fluid in chamber 214 heats smaller diameter tubes 220-222 and thereby the fluid in those tubes 220-222, which is next discharged into chamber 230 to heat larger tubes 207-208 and then flow out through outlet 250.

This improved heat exchanger has about three times the heat transfer efficiency of a similar sized conventional heat exchanger: wherein in input chamber communicates with through a plurality of tubes, through a middle chamber, to an output chamber, having no designed- in backflow.

Fig. 4 is a less expensive but still effective mode of heat exchanger 102 from Fig. 1.

Suction line 100-104 is partly replaced by exchanger section 122A of Fig. 4. In exchanger section 122A, refrigerant flows from compressor 106 through pipe 116 through valve 120 into chamber 300, where manifold 304 splits flow through several copper coils, preferably three coils, of about 30 turns each, shown here as coil 311, and the other two coils shown in part as 312-313. where refrigerant flows through coiled tubes 311-313 and is cooled by fluid in chamber 300. Fluid in chamber 300 is thereby heated so that it leaves chamber 300 as mostly vapor, about 97% vapor, with the refrigerant flowing from line 104 to compressor 106. This again relieves strain on compressor 106, which strain would occur from trying to compress incompressible liquid.

Koh 3 PCT Specification Page 4 August 8, 2009 (1 :26am) Additional improvements have been devised since the priority provisional applications, US 61/087,467, filed 8/8/2008 and 61/103,311 filed 10/7/2008.

In fig. 5, this embodiment optimizes the temperature of the fluid in the suction line 104, for maximum efficiency, to maximize vapor without overheating it. For each refrigerant, there will be different such optimum temperatures, all between 40 and 88 degrees F. Using the R22 that the prototype uses, the literature indicates that optimum temperature is 40 to 60 degrees F. Thermostat 400 is set to, above 60 degrees F, close a circuit 401 and open solenoid valve 404, admitting cold 5 degree F gas to mixing chamber 405, and cooling the fluid flowing into suction line 104 to the optimum 60 degrees F, plus about 5 degrees for hysteresis. Thermostat 400 is set to, below 40 degrees F, close a circuit 408 and open solenoid valve 409, admitting hot 131 degree F gas from output line 108 to mixing chamber 405, and heating the fluid in suction line 104 to the optimum 40 degrees F plus about 5 degrees for hysteresis.

Where the refrigerators supplied by the compressor 106 are spread over a large area, the fluid lines can be difficult to install, and can be vulnerable.

A presently preferred embodiment of suction temperature control is in Fig. 6.

Fig. 7 shows the Peltier heating/cooling device in detail.

Here a self-contained suction vapor heating/cooling block 500 with a thermoelectric Peltier module is wrapped around suction line 104, and a temperature sensor 502, within, is inserted into a hole 503 drilled in suction line 104, to sense the temperature of the refrigerant fluid, such as R-22. Sensor 502 is then soldered 504 into place to seal the hole to keep the R-22 refrigerant within tube 104. Conductors 506-507 conduct the temperature signal to power supply 508 fig. 6, which polarizes and adjusts the current of direct current from power supply 508 across conductors 511-512 to the thermocouple 516 to heat or cool the suction tube 104, as needed to achieve an optimum 40 to 60 degrees F. Heat from or to cooler 516 is conducted across thermal epoxy 518 to heat pipe 520, which is a copper conduit with acetone sealed inside. The acetone evaporates in response to heat and almost instantly transmits the heat

Koh 3 PCT Specification Page 5 August 8, 2009 (1 :26am) efficiently up through the heat pipe 520, to be transmitted via thermal epoxy 522 to heat sink 524. Coiling fan 526 is driven by motor 527 to move air across fins 530 of heat sink 524, so that the Peltier cooler 516 gives or takes heat to or from the air.

To install the heating/cooling block on suction line 104: drill hole 503 in line 104; solder sensor 502 to secure and seal it into the hole 503; Connect sensor 502 via wires 506-507 to power supply 508. Coat a surface of tube 104 with thermal epoxy 518.

Bend legs 531-532 of cooler 516 and refrigeration or heat pipe 520 around tube 104 to make a snug thermoconductive fit with the epoxy. Connect cooler 516 by wires 511-512 to power supply 508. Coat a surface of heat pipe 520 with thermal conductive epoxy 522. Slide heat sink 524 onto heat pipe 520, and keep snug until the thermoconductive epoxy 522, there-between, sets and joins sink 524 to pipe 520. Connect the fan wires 541-542 from fan 527 to power supply 508, fig.6.

In fig. 6, a similar or identical self-contained liquid cooling block 502A with a thermoelectric Peltier module is wrapped around expansion valve feed line 545, and a temperature sensor similarly placed within line 545, senses said fluid's temperature. Power supply 508 polarizes and adjusts the current of direct current from power supply 508 across the Peltier device 502A to heat or cool the line 522 as needed to achieve an optimum 60 degrees F, into expansion valve TVX 550.

Space Heating Mode

Fig. 8 shows how improved auxiliary heat exchanger 102 results in a dramatic efficiency improvement, in which the building heating system heat pump works at lower ambient temperatures, e.g.: 20° F., than the 35° F of a conventional heat pump, in the heating mode.

Koh 3 PCT Specification Page 6 August 8, 2009 (1 :26am) Figure 8 shows the present heat pump system, generally designated 690 in its heating mode. The heat pump system 690 comprises an indoor unit 704, and an outdoor unit 706. Indoor unit 704 includes heat exchanger 708, and fan 711 which blows indoor air across heat exchanger 708, to heat or cool an indoor space. In this drawing it is heating.

Within the outdoor unit 706, motor 717 driven compressor 106 compresses a refrigerant, such as R-22, to drive the refrigerant towards 4-way- valve 719, which switches the system between heating (shown here) and cooling modes. An out door heat exchanger 720 adds (in this heating mode) or removes heat from the system. Auxiliary heat exchanger 102 is an improved unit as in Fig. 3.

Compressor 106 pumps out refrigerant as a high pressure hot gas, at perhaps 140° Fahrenheit through compressor output tube 730 through 4-way valve 19, which is switched in its heating mode to send the refrigerant through tube 732 towards indoor heat exchanger 708. This 140° gas enters indoor heat exchanger 708, where it transfers its heat to the indoor air, which fan 11 blows across heat exchanger 708. Refrigerant exits heat exchanger 708 through tube 734 as high-pressure mid-temperature (perhaps 75 degrees) gas and liquid. These pass through capillary tube 736, which drops their pressure and temperature to about 45 degrees F.

Throughout this specification, temperatures and pressures are approximate, and may vary with time. These temperatures assume an increased efficiency that occurs in this system after the compressor has been running for an interval.

Refrigerant is about 45° F as it enters the improved auxiliary heat exchanger 102, at inlet 200 as in Figure 3.

The improved heat exchanger 102 tends to more efficiently equalize the temperature, so that the gas exits output 216 at perhaps 35 ⁰F, and the liquid exits through outlet 250 at about 30⁰F, from whence it flows through tube 779, towards outside heat exchanger 720 .

Koh 3 PCT Specification Page 7 August 8, 2009 (1 :26am) At the inlet of outside heat exchanger 720 is a orifice 774. Orifice 774 is a restriction in pipe 779's diameter, which restriction decompresses the liquid refrigerant and drops its pressure and temperature towards R-22's -41⁰F vaporization temperature, as it flows through heat exchanger 720.

The combination of: improved heat exchanger 102, and orifice 774 make a colder refrigerant within outside air heat exchanger 720. Thus, this colder R-22 can extract more heat from outside air at lower temperatures than the conventional outside air heat exchanger. The present invention in Fig. 8 will extract heat from outside ambient air down to 20⁰F, making heat pumps economically usable in higher latitudes than before.

Assuming a 20⁰F ambient outdoor air, heated R-22 exits heat exchanger 720 at outlet line 778, at about 15°F. The R-22 flows through 4-way valve 719, which in the heating mode directs it to gas input 212 of auxiliary heat exchanger 102, shown also in Fig. 3, where in middle chamber 214 it flows around tubes 207-208 and 220-222, to cool the liquid in those tubes and absorb heat so that it exits outlet 62 at about 35°F.

Gas outlet 216 is the suction line of Fig. 8, leading warm mostly gas to input 104 of compressor 106. If this gas is too hot, it tends to burden the compressor 106. On warmer days, this system might prove too efficient and warm the suction line to a temperature that overpressures the suction line 104, and thus overburdens the compressor.

Because improved auxiliary heat exchanger 102 is so much more efficient, this gas can exceed optimum temperatures. We have therefore inserted a novel suction pressure control switch 794 to sense if the pressure of this gas is at or above 22 kg. per square centimeter. If so, the suction pressure control switch 94 switches off a relay which controls fan 776, to limit heat absorption at heat exchanger 720, and thus reduce the downstream temperature and pressure of the gas at inlet 104 of compressor 106. This limits the temperature of gas exiting compressor 106 at outlet 730 to 140⁰F.

Koh 3 PCT Specification Page 8 August 8, 2009 (1 :26am) Alternatively, and preferably, we can use the mixing valve arrangement 400 to 408 described in Fig. 5, to optimize the suction temperature at suction tube 104.

As the presently preferred embodiment, we can use the peltier device 500 of fig. 6 to optimize the suction temperature at suction tube 104.

The result of this increased efficiency is:

1. Lower energy consumption, by as much as 40%;

2. The ability to use the heat pump to heat indoor air when outside ambient air temperatures are as low as 20⁰F; which is 15°F lower than with conventional heat pumps; and

3. The resulting ability to economically use heat pumps for heating at higher latitudes than previously economic.

Air-Conditioning Mode

When 4 way valve 719 is switched to the air-conditioning mode, as in Fig. 9, similar efficiencies are also available.

In the air-conditioning mode, the reversed flow will happen with the auxiliary heat exchange 102 structure of Fig 3. 200 becomes the outlet, and 250 becomes the inlet.

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