US20030159458A1

US20030159458A1 - Dual phase condenser system

Info

Publication number: US20030159458A1
Application number: US10/082,871
Authority: US
Inventors: Wei Fang; Way-Jone Hsiao; Ming-Li Tso
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-25
Filing date: 2002-02-25
Publication date: 2003-08-28

Abstract

The present invention relates to a dual phase condenser system, including an air-cooled portion, a water-air-cooled portion and a fan. The air-cooled portion can be further divided into two sectors, wherein the external air, drawn by the fan, passing through the second sector of the air-cooled portion first then to the water-air-cooled portion. The ability of air absorbing water vapor can be increased significantly in the water-air-cooled portion due to the increase of vapor pressure deficit (VPD) of the air passing through the air-cooled portion of the condenser. The dual phase condenser system of this invention is a 3-stage air-cooled condenser when shortage of water occurred. By separating gaseous and liquid refrigerants, the ability of removing thermal energy of the refrigerants can be increased. This invention required no extra fans, thus the EER can be increased when compared with the traditional one stage or patented two-stage air-cooled condenser. The dual phase condenser system of this invention is a 2-stage air-cooled plus 1-stage water-air-cooled condenser when water supply is not a constraint. This design retains the advantage of the water-air-cooled condenser when water is available and avoids its inherit disadvantage when no water is available or under humid condition, thus making it more functional than the patented water-air-cooled condenser.

Description

FIELD OF THE INVENTION

Condenser is one of the devices in an air conditioning and refrigerating system. It is a chamber for refrigerant to change state from superheated gas to saturated liquid and/or sub-cooled liquid by dissipating heat. This invention relates to dual phase condenser system, which consists of an air-cooled portion, a water-air-cooled portion and a fan. The air-cooled portion can be further divided into two sectors. Through the convergence of higher number of refrigerant pipes to a less number of pipes, the gaseous and liquid refrigerants can be separated based on different compressibility. The amount of thermal energy removed of the refrigerants can be increased without using extra fans, thus the EER can be increased when compared with the traditional one stage or patented two-stage air-cooled condenser. The water vapor absorbing ability of air can be increased significantly in the water-air-cooled portion due to the increase of vapor pressure deficit (VPD) of the air passing through the air-cooled portion prior entering to the water-air-cooled portion. The air with higher VPD has the better capability to absorb moisture compare with the air not passing through the air-cooled portion of the condenser especially under the humid weather condition. The better capability of removing vaporized water sprayed on the surface of the condenser means capable of absorbing more latent heat of vaporization. The combination of the above-mentioned portions allows the water-air-cooled portion still functional even under high humidity or no water available conditions, thus making it more functional than the patented water-air-cooled condenser.

PRIOR ART

The style of dissipating heat of the heat exchange device in traditional air conditioning and refrigerating system is the air-cooled type and water-cooled type. The air-cooled type dissipates the sensible heat by utilizing the temperature difference between external air and the surface of the fins and pipes of the condenser. In addition, during the course of persistently dissipating heat of the air-cooled condenser, the temperature gradient, between air and refrigerants, becomes smaller and the efficiency of dissipating heat begins deteriorating, causing the liquid-vapor-ratio of the saturated refrigerants leaving the condenser cannot be raised to a higher extent. This is the reason why the EER of traditional air-cooled air conditioning and refrigerating system cannot be considerably raised. In addition, during the course of dissipating heat, liquid refrigerants and vapor refrigerants always co-exit in the condenser. Therefore, both states cannot be efficiently dissipating heat; moreover, a pressure loss caused from the friction between liquid refrigerants and inner surface of pipe is often neglected, and this pressure loss results in great pressure drop before entering the expansion valve. This is another drawback of such a traditional air conditioning and refrigerating system. In order to improve such drawbacks of the heat exchange device of the traditional air conditioning and refrigerating system, the conventional technique as shown in FIG. 1 is an air-cooled conditioning and refrigerating system with 2-stage condensers. The super-heated refrigerants leaving the

compressor

10, enters the 1st stage condenser 12

thru pipe

11. A heat-dissipating fan 13, which is used to blow air into the 1st stage condenser 12 for the purpose of dissipating heat of high temperature, superheated refrigerants. After the condenser performs heat exchange with external air, the refrigerant converts from the superheated vapor state into the saturated state with co-existence of liquid and vapor. The liquid-vapor ratio of the saturated refrigerant is increased along the pathway of the pipe. As it reaches the outlet of the 1st stage condenser 12, the liquid-vapor ratio reaches the highest value. Then, the saturated refrigerant with co-existence of liquid and vapor enters the 2nd stage condenser 15

thru pipe

14. Another fan 16 is used to blow air to the 2nd stage condenser. After completing the dissipation of heat at the 2nd stage condenser, it is ensured that the refrigerant reaches saturated liquid state or even reaches sub-cooled state. As shown by dotted line of FIG. 1, there are 2-stage condensers. Leaving the 2nd stage condenser, the refrigerant is sent to an expansion valve 18 via pipe 17. Passing through the expansion valve 18, the pipe pressure is lowered and the temperature of the refrigerant is decreased. The low temperature and low pressure refrigerant is then sent to an evaporator 19. During the almost isobaric process, the refrigerant absorbs thermal energy from outside air. Non-evaporated refrigerant liquid and vapor flow from the evaporator into the accumulator 20. Vapor separated from the liquid within the accumulator, flows to the suction inlet of the compressor 10 to complete a full cycle of the refrigerant of the whole system.

The above-mentioned 2-stage condensers includes; 1. The 1st stage condenser equipped with regular fans; 2. The 2nd stage condenser equipped with high-speed fans; 3. A pipe with smaller diameter (neck pipe) connects two condensers. Due to the fact that the gas is much more compressible than liquid, thus they can be separated after passing thru the neck pipe. In an ideal operating condition, the superheated and saturated vapor refrigerants retained in the 1st condenser and the saturated liquid refrigerants flow into the 2nd condenser. The first condenser uses regular fans to dissipate heat. The temperature of the exhausted air of the 1st stage condenser is higher than the air temperature passing through the condenser of a traditional air conditioning system. The capability of heat dissipating of the 2nd stage condenser is not as good as the 1st stage, thus requiring high-speed fans to remove necessary amount of thermal energy with less pressure drop within the system. Indeed, the above-mentioned 2-stage condensers can considerably raise the ability of dissipating heat and got the invention patent of Taiwanese (No. 129153) and U.S. Pat. No. 6,092,377. However, compared to the conventional air conditioning and refrigerating system, due to the fact that this design requires extra condenser and extra high-speed fans, it increases power consumption; thus, there is no great improvement of EER.

Water-air-cooled condenser can remove more thermal energy of refrigerant due to the fact that the latent heat of vaporization is much bigger than sensible heat. Taiwanese Patent No. 156031, as shown in FIG. 2, includes a

compressor

20, a condenser 21, a liquid storage vessel 22, an expansion valve 23 and an evaporator 24. Its closure cycle system is formed by many refrigerant pipes, wherein the condenser 21 further includes: a water reservoir 25 which is situated below the condenser 21; a water supply pipe 26 one end of which is connected to the bottom of the reservoir 25 and the other end of which is extended to above and which is connected to pump 27, which sends water to the other end of the water supply pipe 26; many nozzles 28 which installed on the water supply pipe 26 above the condenser 21; fans 29 positioned on the top of the condenser shell; a feed pipe 30, the end of which runs thru the side wall of the water reservoir 25 and the other end of which is connected to a water source. Thus, the water is sprayed on fins of the condenser 21, absorbing thermal energy from the fins of the condenser 21 and then vaporizes. The water vapor is drawn to the outside by the fan 29.

It is expected that the EER of the water-air-cooled type air conditioning system is superior to those of air-cooled type if both operated in the design conditions. Various designs were made to improve the water absorption ability on the surface of the fins and pipes of the water-air-cooled condenser to further increase the EER of the system, for example, wrapping the refrigerant pipes with water absorbing materials. It is the same design that promotes the EER values that limited the amount of heat dissipation of the refrigerants if no water can be supply. They show malfunction under suspension of water or high humidity of external air. It can even arise potential danger if the pressure on the high-pressure side greatly increases due to poor heat dissipation.

Dry weather is ideal for water-air-cooled type air-conditioning system. However, under high humidity weather, especially, during the rainy season, air humidity reaches as high as 90%, even 100%. The humid air has little space for water absorption, thus the capability of removing thermal energy of the refrigerants inside the condenser thru the evaporative cooling process is greatly limited for the conventional water-air-cooled condensers.

SUMMARY OF THE INVENTION

Due to the above drawbacks, i.e. for the conventional air-cooled air conditioner, its energy efficiency EER cannot be greatly raised and for water-air-cooled type, it cannot be normally operated during the shortage of water or in high humidity conditions. Therefore, the main object of this invention is to provide a dual phase condenser system which can raise cooling efficiency without using extra energy and which can still be operated under suspension of water and under highly humid weather condition.

This invention relates to dual phase condenser system, which consists of an air-cooled portion and a water-air-cooled portion. The external air is firstly pass through the air-cooled portion and then the water-air-cooled portion. Within the first portion, the thermal energy of the refrigerant inside the condenser is removed due to the difference of sensible heat. Within the second portion, thermal energy of the refrigerant is used to vaporize the water sprayed on the surface of the condenser. The drier air, passing through the first portion, has the better capability to absorb moisture compare with the air not passing through the first portion of the condenser especially under the humid weather condition. The better capability of removing vaporized water sprayed on the surface of the condenser means capable of absorbing more latent heat of vaporization. By combining two portions mentioned above, the dual phase condenser not only can greatly raise cooling ability with no extra energy consumption, thus increasing EER comparing with traditional one stage or two stage air-cooled condenser, but also can be operated if there is lack of water or under high humidity condition, thus making it more functional than the water-air-cooled condenser.

According to this invention, the air-cooled portion of the dual phase condenser is divided into two sectors accordance with the flow direction of the refrigerant. High-pressure refrigerant, from the outlet of the compressor, flows into several horizontal manifolds at the top of the first sector of the air-cooled portion. The refrigerant flows horizontally, in a top-down fashion and converges at the end of the first sector, then enters the second sector of the air-cooled portion, flows horizontally and in a top-down fashion again. At the end of the second sector, the refrigerant converges again and flows into several horizontal manifolds at the top of the water-air-cooled portion of the dual phase condenser located at the back of the second sector of the air-cooled portion.

Within the pathway of the refrigerant inside the dual phase condenser, it includes diminishing the flow path of refrigerant twice to confine its flow. For example, refrigerants of 4 pipes converge into two pipes with same diameter and then converge to one pipe with same diameter. Due to the fact that gaseous refrigerant is much more compressible than the liquid one, the superheated, saturated vapor, saturated liquid-vapor mixture and saturated liquid can be separated as possible as it can be due to the existence of above-mentioned converges. It is possible that in the first sector of the air-cooled portion, the refrigerant is mostly in gaseous state, and in the second sector of the air-cooled portion, liquid and gaseous co-exist and it is liquid state in the water-air-cooled portion.

The dual phase condenser is a 3-stage air-cooled condenser when shortage of water occurred and is a 2-stage air-cooled plus 1-stage water-air-cooled condenser when water supply is not a constraint. Another merit of this invention of the dual phase condenser is that no extra fans required.

The dry bulb temperature of the Air passing through the air-cooled portion of the dual phase condenser will be increased and the relative humidity will be decreased, thus leading to the increase of the vapor pressure deficit (VPD) of the air. The values of VPD of the air indicate the water vapor absorbing capability. In rainy days with humidity equals 100%, the VPD is 0. Air, before entering the water-air-cooled portion, needs to pass through the second sector of the air-cooled portion to ensure that the VPD of the air will be always above zero, thus making it capable of removing thermal energy of the refrigerant in this portion even the outdoor environment is at 100% humidity.

One more merit of this invention of the dual phase condenser is that the design retains the advantage of the water-air-cooled condenser when water is available and avoids its inherit disadvantage when no water is available or under humid condition.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

For the purpose of illustrating the present invention, the following drawings are provided. The above and other objects, features and efficiency of this invention will be further understood by reading the description of embodiments in conjunction with attached drawings, wherein: [0014]
FIG. 1 is a construction view of conventional air-cooled air condition system with two stages of condenser (Taiwanese Patent No. 129153 and U.S. Pat. No. 6,092,377). [0015]
FIG. 2 is a construction view of a water-air-cooled air conditioning and refrigerating system (cited from Taiwanese Patent Publication No. 156031). [0016]
FIG. 3 is a perspective view of the dual phase condenser system of this invention. [0017]
FIG. 4 is an embodiment view of the embodiment of this invention, which is applied to the air conditioning system. [0018]
FIG. 5 is a perspective view of 5 equivalent variations of the dual phase condenser system of this invention. [0019]

DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENT

Firstly, please refer to FIG. 3, the dual [0020] phase condenser system 100 of this invention is consists of air-cooled portion 101 and water-air-cooled portion 102. The air-cooled portion 101 constructed by many tubes of the refrigerant and fins 120. Refrigerant inside the header pipe 110 is branched into several horizontal manifolds in the front section of the first sector 101. The purpose of this design is to shorten the flow path of the refrigerant and to decrease the number of runs that passes thru the U-tube. The fins 120 dissipate heat by utilizing the sensible heat of the air. This air-cooled portion 101 is divided into the first sector 101 a and the second sector 101 b according to the flow direction of the refrigerant. The water-air-cooled portion 102 constructed by many tubes of the refrigerant and fins 120. In addition, a water pipe 130 is installed on an inner corner of the upper end of water-air-cooled portion 102. Water can be ejected through nozzles or holes at certain interval on the water pipe 130. Mist or fog can be sprayed to the fins 120 and pipes of the refrigerant. The thermal energy of the refrigerant can be removed by providing the water with the latent heat of vaporization. Valve 131 is installed in the water source of the water pipe 130. A timer 132 controls the valve 131 for intermittent water spraying. Fan 103 is used to draw external air flowing through the condenser for heat dissipation.
The [0021] second section 101 b of the air-cooled portion 101 is positioned in front of the water-air-cooled portion 102. External air, blown in by fan 103, is heated firstly so as to increase the VPD, and then it enters the water-air-cooled portion 102. The increase of VPD promotes the ability of absorbing water vapor of air.
As shown in FIG. 4, the basic construction of this embodiment is the same as that of conventional one. It includes: a [0022] compressor 111, a dual phase condenser 100 which includes the air-cooled portion 101 having first sector 101 a and second sector 101 b, a water-air-cooled portion 102 and a fan 103. The inlet of the condenser is connected to the high-pressure side of compressor 111 by header pipe 110. Refrigerant inside the first sector 101 a flows horizontally in a top-down fashion and converges to two header pipes 110 a and 110 b, and then flows to second sector 101 b. Inside the second sector 101 b, refrigerant flows horizontally in a top-down fashion and converges to one header pipe 110 c, then flows to water-air-cooled portion 102. In water-air-cooled portion 102, refrigerant flows horizontally in a top-down fashion and converges to one header pipe 110 d.
An [0023] expansion valve 112, whose end is connected to the outlet end of dual phase condenser 100 thru pipe 110 d, an evaporator 113 whose inlet end is connected to the other end of expansion valve 112 by pipe 110 e, an accumulator 114, the end of which is connected to the outlet of evaporator 113 by pipe 110 f and the other end of which is connected to the low pressure side of compressor 111 by pipe 110 g.
[0024] Water pan 133, positioned below the water-air-cooled portion 102, and in which there is provided with an exhaust water pipe 134 for exhausting surplus water.
Refrigerant converges in [0025] header pipes 110 a, 110 b and 110 c encountered restriction on the cross section area of the pipes. Flow path of refrigerant becomes small to form a neck tube effect for confining the flow of refrigerant. Liquid refrigerant is separated from gaseous refrigerant. Under ideal operating conditions, superheated gaseous refrigerant mostly concentrated in the first sector 101 a, the saturated refrigerant (with high ratio of liquid-vapor) in the second sector 101 b and the saturated liquid refrigerant in the water-air-cooled portion 102.
The course of heat dissipating of the water-air-cooled [0026] portion 102 mainly utilizes the mist or fog, sprayed from the nozzle installed at water pipe 130. Water droplets on the surface of the fins and tubes are heated to evaporate, thus indirectly removing the thermal energy of refrigerant.
Assuming the dry bulb and wet bulb temperature of external air are 35 and 30° C., respectively. The air is drawn into the [0027] second sector 101 b of the air-cooled portion 101 by fan 103 and heated to 40° C. dry bulb temperature before enters the water-air-cooled portion 102. The relative humidity is reduced from 70% to 53% and the VPD is increased from 1.67 to 3.435 kPa. The ability of absorbing water vapor is more than doubled. Even in the rainy day with the humidity reaching 100%, dry bulb temperature increased from 30 to 35° C. can result in the increase of VPD from 0 to 1.38 kPa and decrease of relative humidity from 100 to 75%. Allow external air passing through the air-cooled portion of the condenser prior entering the water-air-cooled portion can overcome the drawback of traditional water-air-cooled condenser.
FIG. 5 shows 5 types of embodiments of the dual [0028] phase condenser system 100 of this invention. FIG. 5a shows the previously mentioned embodiment and other figures show 4 more embodiments with similar construction. Differences between 5 embodiments are the position of fan 103 and the design of dual phase condenser 100.
FIG. 5[0029] a and FIG. 5b show the design of dual phase condenser 100, in which the air-cooled portion 101 and the water-air-cooled portion 102 are combined into a unit.
FIGS. 5[0030] c, 5 d and 5 e show the design of dual phase condenser 100, in which the independent air-cooled condenser 101 and water-air-cooled condenser 102 are connected in series. The first sector 101 a and the second sector 101 b of air-cooled condenser 101, shown in FIGS. 5c, 5 d and 5 e, may also be formed using two independent air-cooled condensers. In addition, either plain pipes or finned pipes can be used in water-air-cooled condenser 102. Any available or future designs suitable for water-air-cooled condenser can be utilized.
In the dual [0031] phase condenser system 100 of this invention, as shown in FIGS. 5a, 5 c and 5 d, fan may be installed in front of the air-cooled condenser 101 or installed at the rear end of the water-air-cooled condenser 102, as shown in FIG. 5b and FIG. 5e. In spite of the location of the fan, the air moves in the same direction.
While this invention has been illustrated and described in accordance with preferred embodiments, it is recognized that variations and modifications may be made therein without departing from the invention as set forth in the claims. [0032]
In summary, the dual phase condenser system of this invention is a 3-stage air-cooled condenser when shortage of water occurred and is a 2-stage air-cooled plus 1-stage water-air-cooled condenser when water supply is not a constraint. This design retains the advantage of the water-air-cooled condenser when water is available and avoids its inherit disadvantage when no water is available or under humid condition, thus making it a better design compare with patented water-air-cooled condenser. Also, the dual phase condenser required only one fan, thus making it a better design compare with the patented 2-stage condenser in term of EER. [0033]
List of Elements: [0034]
[0035] 100 the dual phase condenser system of this invention
[0036] 101 air-cooled portion
[0037] 101 a first sector of air-cooled portion
[0038] 101 b second sector of air-cooled portion
[0039] 102 water-air-cooled portion
[0040] 103 fan
[0041] 110, 110 a, 110 b, 110 c, 110 d, 1103, 110 f, 110 g pipes
[0042] 111 compressor
[0043] 112 expansion valve
[0044] 113 evaporator
[0045] 114 accumulator
[0046] 120 fins
[0047] 130 water pipe
[0048] 131 valve
[0049] 132 timer
[0050] 133 water pan
[0051] 134 exhaust pipe

Claims

What is claimed is:

1. A dual phase condenser system includes an air-cooled portion and a water-air-cooled portion and a fan.

2. The dual phase condenser system according to claim 1, wherein the air-cooled portion is divided into a first sector and second sector according to the flow direction of the refrigerant, the piping of the refrigerant which comes from the high pressure side of the compressor being branched into many horizontal manifolds at the front section of the first sector flowing from up to down, after the refrigerant converges at the top of second sector, it runs horizontally and in top-down fashion and then converges again at the bottom of second sector, refrigerant then send to the top of the water-air-cooled portion.

3. The dual phase condenser system according to claim 1, wherein one (or more) piping of water source is (or are) installed on the internal corner of the upper side of water-air-cooled portion, and nozzles are installed or holes are drilled on such piping.

4. The dual phase condenser system according to claim 1, wherein the refrigerant firstly flows to the air-cooled portion, then into the water-air-cooled portion.

5. The dual phase condenser system according to claim 1, wherein the refrigerant firstly flows to the water-air-cooled portion, then into the air-cooled portion.

6. The dual phase condenser system according to claim 1, wherein in spite of the location of the fan, air is drawn into the air-cooled portion first then into the water-air-cooled portion.

7. The dual phase condenser system according to claim 1, wherein the dual phase condenser system is constructed by connecting, in series, an independent air-cooled condenser and independent water-air-cooled condenser.

8. The dual phase condenser system according to claim 2, wherein the first and the second sectors of the air-cooled portion are constructed using two independent air-cooled condensers.