DE29910929U1 - Evaporative condenser - Google Patents

Description

GLAWE ₁ DELFS ₁ MOLL & PARTNER

Fu Chin Liu

Taiwan, Republic of China

APPROVED VE^

RICHARD GLAWE, Dr.-Ing. (1952-1985)

KLAUS DELFS, Dipl.-lng., Hamburg

WALTER MOLL, Dipl.-Phys. Dr. rer. nat., Munich

HEINRICH NIEBUHR, Dipl.-Phys. Dr. phil. habil., Hamburg

ULRICH GLAWE, Dipl.-Phys. Dr. rer. nat., Munich BERNHARD MERKAU, Dipl.-Phys., Munich CHRISTOF KEUSSEN, Dipl.-Chem. Dr. rer. nat., Hamburg

PO Box 26 01 62 80058 Munich

Liebherrstrasse 20 80538 Munich

Tel. (089) 22 46 65 Fax (089) 22 39 38 (G3) Telex 5 22 505

HAMBURG,

PO Box 13 03 91 20103 Hamburg

Rothenbaumchaussee 58 20148 Hamburg

Tel.(040)4 10 20 08

Fax (040) 45 89 84 (G4.G3)

&rgr; 19798/99 N/kml801

Evaporative condenser

The present invention relates to an evaporative condenser for use in an air conditioner (cooling device).
5

Air conditioners (or air conditioning units (cooling devices)) are used extensively in most countries during summer to air-condition buildings, rooms, trains, motor vehicles, etc. When an air conditioner is operating, it consumes a lot of energy. In a typical air conditioner, a refrigerant in a liquid state is passed to an evaporator to perform heat exchange with air, which allows cooling air to be passed into the interior of a building, room, train or motor vehicle. After the heat exchange process, the refrigerant in the liquid state is

ic state is converted to the gas state, the gas state refrigerant is then compressed by a compressor and pumped to a condenser, where the gas state refrigerant is converted back to the liquid state. The condenser units of conventional air conditioners include three types, namely the air-cooling type, the water-cooling type and the evaporative type. An air-cooling type air conditioner uses convection air currents to remove heat from its condensing unit. In order to remove the heat quickly, a large air contact area and high air currents are required. Therefore, an air-cooling type air conditioner is heavy, requires a lot of power and generates a lot of noise during its operation. A water-cooling type air conditioner uses cooling water to remove heat from its condensing unit. However, a water-cooling type air conditioner is expensive and requires a lot of cooling water. The installation of a water tower for a water-cooling type air conditioner is complicated and can cause American veterans syndrome. An evaporative type air conditioner removes heat by evaporating water (one liter of water absorbs about 539 kcal when it evaporates). The heat removal effect of an evaporative type air conditioner is much better than that of an air-cooling type air conditioner and a water-cooling type air conditioner. However, when an evaporative type air conditioner is used, water storage means are required to absorb excess water that has not evaporated in the evaporative condenser unit of the air conditioner.

The present invention has been made to provide an evaporative condenser for an air conditioner which avoids the above disadvantages. An object of the present invention is to provide an evaporative condenser which enables the supplied cooling water to be completely evaporated so that the heat can be effectively dissipated during its operation. It is a further object of the present invention to provide an evaporative condenser which is compact, has all the individual parts in it and can be conveniently installed in an air conditioner. Finally, an object of the invention is to greatly improve the operating efficiency of the air conditioner (cooler).

According to one aspect of the present invention, the evaporative condenser comprises an evaporative condenser unit for condensing a gaseous refrigerant into the liquid state, the evaporative condenser unit comprising a plurality of condenser coils or windings and absorbent material covering the condenser coils, a low compression ratio compressor controlled to pump a gaseous refrigerant into the evaporative condenser unit, a water supply system comprising a control PC board and an electromagnetic valve controlled by the control PC board to allow cooling water to be supplied from a water source to the layer of absorbent material of each condenser coil, and a condenser blower or fan controlled to force air flows through gaps in the condenser coils of the evaporative condenser unit.

whereby heat is removed from the evaporative condenser unit. According to another aspect of the present
Invention, each of the condenser coils comprises a metal coil tube and a layer of absorbent
Material covering the circumference of the metal coil tube,
and the water supply system comprises a plurality of water spray tubes and absorbent material that
covers the water outlet openings of the water spray tubes so that supplied cooling water is evenly distributed over the absorbent material of the condenser coils
can.

The invention is described below using advantageous embodiments with reference to the accompanying drawings. They show:

Fig. 1 is a liquid-gas curve obtained from R-22 refrigerant;

0 Fig. 2 is an exploded view of an air conditioner constructed in accordance with the invention;

Fig. 3 is a perspective view of the device shown in Fig. 2

Air conditioners;
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Fig. 4 is a perspective view of an evaporative condenser unit of the invention;

Fig. 5 is a perspective view of an alternative form of evaporative condenser unit according to the invention;

Fig. 6 is an exploded view of the evaporative condenser unit shown in Fig. 4 ;

Fig. 7 is a perspective view of a condenser coil according to the invention;

Fig. 7A is an enlarged view of a portion of Fig. 7;

Fig. 8 is a schematic diagram showing the arrangement of the water spray tubes, the water supply pipe and the electromagnetic valve of the water supply system of the invention;

Fig. 9 is an R-22 Mollier diagram obtained from a conventional capacitor unit;

Fig. 10 is an R-22 Mollier diagram obtained from an evaporative condenser unit according to the invention; and
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Fig. 11 is a perspective view of a combination of the capacitor device according to the invention.

Fig. 1 is the liquid-gas curve obtained from the R-22 refrigerant. As mentioned, the refrigerant can be easily condensed with low condensation pressure when it is at a low temperature. When it is at a temperature of 45 ⁰ C, the theoretical value of the relative pressure is about 18 kg/cm ² . When the temperature drops to 30 ⁰ C, the theoretical value of the relative pressure can drastically decrease to 12.2 7 kg/cm ²

Therefore, reducing the working pressure of the compressor for the condenser of an air conditioner or refrigeration system can greatly save the consumed power (horsepower) that drives the compressor, thus improving the efficiency of the air conditioner or refrigeration system. The present invention is based on the rule that the condensing temperature is directly proportional to the condensing pressure during the change of a refrigerant between the liquid state and the gaseous state.

Referring now to Figures 2 and 3, the low compression ratio compressor 10 is operated to pump a gaseous refrigerant, which is at high pressure and temperature, into an evaporative condenser unit 20 for condensation into the liquid state. A water supply system 40 is controlled by a control PC board 404 to periodically supply water to the evaporative condenser unit 20. A condenser fan 60, which includes a fan motor 604 and a fan blade assembly 602, is controlled to cause air flows through air passages in the evaporative condenser unit 20, thereby causing heat and moisture to be rapidly removed from the evaporative condenser unit 20. The control PC board 404 includes a water pressure selector switch for selecting high, medium and low water pressure. The control PC board 404 controls an electromagnetic valve 402 of the water supply system 40 and causes the electromagnetic valve 402 to be closed/opened based on the operating cycle of the compressor 10 so that sufficient water can be supplied to the evaporative condenser unit 20 to cool the refrigerant.

tel and to cool the compressor 10. During operation of the compressor 10, supplied water is evaporated by the heat and residual water, if any, is collected for repeated use. The electromagnetic valve 402 controls the passage of water between the water source, which may be, for example, a waterworks, and the water supply pipe with reference numeral 412 of the water supply system 40. The water supply system 40 further comprises a manual switch 406 which is controlled to continuously supply water for washing the machine, and a plurality of water spray pipes 408 connected to the water supply pipe 412 and installed in the evaporative condenser unit 20.

Referring now to Figures 4 and 5, the evaporative condenser unit 20 may have a straight shape as shown in Figure 4 or a curved shape as shown in Figure 5. The evaporative condenser unit includes a plurality of support frames 206, a plurality of independent condenser coils 204 secured to the support frames 206 and arranged in parallel or staggered relationship for circulation of a coolant, the condenser coils 204 covered with absorbent material 202 and defining a plurality of air gaps 212 between the portions thereof, and a plurality of packing frames 208 secured to the support frames 206 with screws for securing the condenser coils 204 and the support frames 206 together. In addition, the water spray tubes 408 of the water supply system 40 (see also Fig. 2) are attached to the support frame 206 at different heights and are controlled to spray water over the condenser

• ft»··· · ft

8th

coils 204. The water spray tubes 408 are covered with absorbent material 410 so that the sprayed water can be adsorbed by the absorbent material 410 and then evenly distributed over the condenser coils 204.

Referring now to Figures 7 and 7A, the condenser coil 204 includes a metal coil tube 210 and a band of absorbent material 202 spirally wrapped around the metal coil tube 210. Alternatively, the absorbent material 202 may be made in the form of a sleeve and sleeved onto the condenser coil 204. The absorbent material 202 may be obtained from nonwoven fabric, cloth, natural fibers, synthetic fibers, reclaimed fibers, inorganic fibers, etc.

Referring to Fig. 8, the water spray tubes 408 may be round tubes or flat tubes. The water outlets of the water spray tubes 408 may be formed to have a narrow elongated shape or a circular shape. Each water spray tube 408 has a diameter that gradually decreases from the water supply tube 412 toward the end so that cooling water can be uniformly distributed to the evaporative condenser unit 20.

As mentioned above, the evaporative condenser unit 20 is constructed of a plurality of condenser coils, each condenser coil 204 comprising a metal coil tube 210 covered with a layer of absorbent material 202. When cooling water

discharged from the water spray tubes 408 of the water supply system 40, it is absorbed by the absorbent material 202 of the condenser coil 204 for heat exchange with the coolant flowing through the coil tubes 210 of the condenser coils 204, allowing heat to be quickly carried away by air currents passing through the air gaps 212 in the evaporative condenser unit 20. Since the electromagnetic valve 402 of the water supply system 40 is controlled by the control PC board 404, the amount of cooling water supplied from the water supply system 40 to the evaporative condenser unit 20 can be controlled approximately to the amount of water evaporated during operation of the machine.

Fig. 9 shows an R-22 Mollier diagram obtained from a conventional condenser unit. Fig. 10 shows an R-22 Mollier diagram obtained from an evaporative condenser device according to the present invention. In Fig. 9, the temperature of the gaseous refrigerant at the inlet port of the condenser unit is about 80 ⁰ C, the temperature of the liquid state refrigerant at the outlet port of the condenser unit is about 37 ⁰ C, and the condenser pressure is about 2 0 kg/cm ² -a. In Fig. 10, the temperature of the gaseous refrigerant at the inlet port of the evaporator device is about 6O ⁰ C, the temperature of the refrigerant in the liquid state at the outlet port of the evaporator condenser device is about 3O ⁰ C, and the condenser pressure is about 14 kg/cm ² -a (theoretically, the condenser pressure in the case of R-22 at 3O ⁰ C is about 12.27 kg/cm ² -a, see Fig. 1). Since the compression ratio

ratio is reduced, the temperature of the condensed refrigerant can be reduced by about 7 ⁰ C, so that the efficiency is improved by about 20%. Since the compression ratio is greatly reduced, the consumed power of the compressor 10 can be reduced by about 25% as compared with an equivalent conventional unit. Therefore, with the evaporative condenser device of the present invention, the power consumption of an air conditioner or refrigerator can be greatly reduced, and its efficiency EER (or COP) value can be increased by about 50%. According to experiments conducted on model RC870489 obtained from Shuan-Shih Electric Engineers Taiwan at the Airconditioner Department of Hsu-lin Laboratory of Taiwan Power Research and Test Center, the EER value is as high as 4.027 kcal./hW (COP 4.68). As compared with equivalent conventional devices, the power consumption is reduced by about 40%.

Referring to Fig. 11, the evaporative condenser unit 20 may be attached to an ordinary air cooling condenser 80 to form a combination condenser device.

The invention can be summarized as follows. The evaporative condenser device is used in an air conditioner to reduce the power consumption of the air conditioner and to increase its efficiency. The evaporative condenser device is based on the rule that the condensation temperature is directly proportional to the condensation pressure during the change of the refrigerant between the liquid state and the gas state. The evaporative

condenser apparatus comprises an evaporative condenser unit for condensing a gaseous refrigerant into a liquid state, the evaporative condenser unit comprising a plurality of condenser coils and absorbent means covering the condenser coils, a low compression ratio compressor controlled to pump a gaseous refrigerant into the evaporative condenser unit, a water supply system comprising a control PC board and an electromagnetic valve controlled by the control PC board to allow cooling water to be supplied from a water source to the layer of absorbent material of each condenser coil, and a condenser fan or blower controlled to draw air currents through the spaces in the condenser coils of the evaporative condenser unit and to carry heat away from the evaporative condenser unit.

It will be understood that the drawings are for illustration purposes only and are not intended to be a definition of the limits and scope of the invention disclosed herein.

Claims (7)

Protection claims 1.Evaporative condenser with an evaporative condenser unit for condensing a gaseous coolant into the liquid state, which has a plurality of condenser coils with a compressor which is controlled for pumping the gaseous coolant into the evaporative condenser unit, and with a water supply system, characterized in that that the plurality of condenser coils (204) are covered with absorbent media (202); that the compressor (10) is a low compression ratio compressor ; that the water supply system (40) comprises a control PC board (404) and an electromagnetic valve (402) controlled by the control PC board (404) for supplying water from a water source to the layer of absorbent material (202) of each of the condenser coils (204) of the evaporative condenser unit (20); and that a condenser fan or blower (60) is provided which has a fan motor (604) and a fan blade assembly (602) driven by the fan motor (604) to draw air through spaces in the condenser coils (204) of the evaporative condenser assembly (20) and thereby remove heat from the evaporative condenser assembly (20). 2. Evaporative condenser according to claim 1, characterized in that the control PC board (404) of the water supply system (40) has a selector switch for selecting high hem, medium and low water pressure and controls the operation of the electromagnetic valve (402) based on the operating cycle of the low compression ratio compressor (10), which enables cooling water to be periodically supplied to the evaporative condenser unit (20) in such a way that the evaporation rate of the water at the evaporative condenser unit (20) is approximately equal to the supply amount of cooling water from the water supply system (40). 3. Evaporative condenser according to claim 1 or 2, characterized in that the water supply system (40) comprises a water supply pipe (412) having a water inlet end connected to the electromagnetic valve (402) and a water outlet end and a plurality of water spray pipes (408) connected to the water outlet ends of the water supply pipe (412) for supplying cooling water to the condenser coils (204), the water spray pipes (408) having a diameter gradually decreasing from the water supply pipe (412), a plurality of water outlets directed toward the condenser coils (204) and an absorbent material (410) provided at the water outlets. 4. Evaporative condenser according to one of claims 1 to 3, characterized in that the water supply system (40) further comprises a manual switch (406) by means of which continuous water supply to the evaporative condenser unit (20) can be set. • I * * 5. Evaporative condenser according to one of claims 1 to 4, characterized in that the evaporative condenser unit (20) has at least one support frame (206) which supports the condenser coils (204) and at least one packing frame (208) which is attached to the support frame (206) in order to hold the condenser coils (204) in place. 6.An evaporative condenser according to any one of claims 1 to 5, further comprising a radiator fin type condenser unit for air cooling attached to the evaporative condenser unit (20). 7. Evaporative condenser according to one of claims 1 to 6, characterized in that the condenser coils (204) each comprise a coil tube (210) made of metal and a layer of absorbent material (202) covering the periphery of the coil tube (210) made of metal.