JPS5892745A - Hot water supply device - Google Patents

Abstract

PURPOSE:To enable to supply the highly hot water by a system wherein the refrigerant makes the water supply amount of water heater in the overheated gaseous phase less than that of supply water heater in the vapor and liquid phases. CONSTITUTION:The first and second heat exchangers 22, 23 for heating water supply are provided in series together with a compressor 12, pressure-reducing device 13 and heat collecting heat exchanger 11 to constitute a refrigetating cycle. In such a constitution, the refrigerant in the tube 24 in the first heat exchanger 22 forms over-heated gaseous phase while that in the tube 25 in the second heat exchanger forms vapor and liquid phases. The water tubes 26, 27 of both heat exchangers 22, 23 are connected to the hot water reservoir 15 in series through a pump 9 making the intermediate temperature water circulating channel 35 diverge from the position between the water tube 26 and 27 to the intermediate temperature reservoir 15b in said hot water reservoir 15 while connecting the high temperature water circulating channel 34 to the high temperature water reservoir 15a. Both circulating channels 34, 35 are provided with water temperature detectors 38, 39 and flow rate controlling valves 36, 37 making the water supply amount in the water tube 26 less than that in the water tube 27.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water heater that heats water supply by condensing a refrigerant using a heat collecting circuit.

In FIG. 1, a conventional water heater is shown. 1 is a hot water tank,
2 is a water supply pipe, 3 is a pressure reducing check valve provided in the water supply pipe 2, 4 is a hot water supply pipe, 5 is a hot water tap, 6 is a heat insulating layer provided on the outer surface of the hot water storage tank 1, and 7 is a forced convection type water supply heating device. It is a heat exchanger, and the water supply side passage 7a and the heat collection circuit side passage 7b are thermally connected.

8 is a heat insulating layer provided on the outer surface of the heat exchanger 7 for heating the water supply, 9 is a pump for circulating the water supply, 1o is the lower part of the hot water storage tank 1, pump 9 is a water circulation system that sequentially connects the water supply side passage 71L and the upper part of the hot water storage tank 1. It is a road. 11 is a heat exchanger for collecting heat, 12 is a compressor, 1
3 is a pressure reducing device, and these heat collecting heat exchangers 11. Compressor 12. Heat collection circuit side passage 7b.

The pressure reducing devices 13 are sequentially connected by piping 14 to form a closed circuit, and a suitable amount of refrigerant (for example, R-22) is sealed in this closed circuit.

In the water heater having the above configuration, the water supply heating operation operates the compressor 12 and circulates the refrigerant in the direction of the broken line arrow A in the figure.
The high-pressure, high-temperature superheated gas refrigerant discharged from the compressor 12 radiates heat to the water circulating in the direction of the solid line arrow in the figure by operating the pump 9 in the feedwater heating heat exchanger 7, heating the water, and condensing it due to the heat radiation. The refrigerant is a high-pressure liquid refrigerant. This high-pressure liquid refrigerant is depressurized by the pressure reducing device 13 to become a low-pressure, low-temperature refrigerant and enters the heat collecting heat exchanger 11. Here, the refrigerant absorbs heat from the outside and sequentially evaporates to become a low-pressure gas refrigerant, and the compressor 12 sucks in this low-pressure gas refrigerant and discharges the high-pressure, high-temperature superheated gas refrigerant, thereby forming a feed water heating cycle.

In FIG. 2, the vertical axis is the temperature T1, and the horizontal axis is the heat transfer region M, and solid lines indicate changes in the refrigerant temperature Tn and n hot water Tw in the feed water heating heat exchanger 7. tRi is refrigerant inlet temperature, type is refrigerant condensation temperature, tRo is refrigerant outlet temperature, twi is water inlet temperature, two is water outlet temperature, G is refrigerant superheated gas region, P
is a two-phase region where the refrigerant is condensed and gas and liquid coexist, and L is a supercooled liquid region, where the refrigerant flows in the direction of the broken line arrow C and the water flows in the direction of the solid line arrow 2, forming counterflows.

Here, tRi is 80~1bo0C1tRC is 60~6
6°C, two is about 46 to 600C, but what is required for a water heater is the hot water supply temperature, that is, the water outlet temperature t.
Wow or even higher. In this conventional example, the upper limit of the water outlet temperature two is when the water temperature twc in the refrigerant condensation start region or the refrigerant condensation temperature tRC is reached, which is the state shown by the broken line Tw/ in the figure. In order to make twc≠tRc, the heat transfer area of the heat exchanger should be made very large, or the increase in temperature of two obtained by increasing the size of the heat exchanger is small compared to the cost increase, so this plan is not realistic. tw
Another way to increase o is to raise the refrigerant condensing temperature tRc, but in this case, the pressure of the refrigerant increases, and there is a problem that the condensing temperature cannot be raised too high in order to ensure the reliability of refrigerant circuit components.

An object of the present invention is to obtain high-temperature hot water supply by making the amount of water in the water side circuit, which is thermally opposed to the refrigerant superheated gas region, smaller than the total amount of circulating water.

In order to achieve the above object, the present invention arranges a first feedwater heating heat exchanger and a second feedwater heating heat exchanger in series, and the first
A hot water outlet is provided in the water side connecting path connecting the feed water heating heat exchanger and the second feed water heating heat exchanger, and with this configuration, the amount of water in the first feed water heating heat exchanger can be changed to the amount of water in the second feed water heating heat exchanger. The first water supply heating heat exchanger obtains high-temperature hot water.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 16 is a partition wall 1 having a hole 16 passing through it.
It is a hot water storage tank whose interior is divided into upper and lower parts by 7, and consists of an upper high temperature water tank 16& and a lower medium temperature water tank 16b. 18 is a hot water supply pipe for high temperature water, 19 is a hot water supply tap for high temperature water, 2o is a hot water supply pipe for medium temperature water, and 21 is a hot water supply tap for medium temperature water. 22 is a first feed water heating heat exchanger, and 23 is a second feed water heating heat exchanger, which are connected to a heat collecting circuit side passage 24.25 and a water supply side passage 26.2, respectively.
7 is thermally coupled. The passages on the heat collecting circuit side and the water supply side of the first and second feed water heating heat exchangers 22 and 23 are connected in series by connecting passages 28 and 29. 30 is a water supply inlet of the second water supply heating heat exchanger 23, 31 is a first water outlet serving as a water side outlet of the first water supply heating heat exchanger 22, and 32 is a second water outlet provided in the water side connection path 29. It is. 33 is a water supply circulation path connecting the lower part of the hot water storage tank 15 and the water supply population 3o;
4 is a high temperature water circulation path connecting the first tap 31 and the high temperature water tank 16a1, and 36 is a medium temperature water circulation path connecting the second tap 32 and the medium temperature water tank 16b. 36 and 37 are flow control valves provided in the high temperature water circulation path 34 and the medium temperature water circulation path 36;
38 and 39 are water temperature detectors provided in the high temperature water circulation path 34 and medium temperature water circulation path 35, and flow rate control valves 36 and 37.
and water temperature detectors 38 and 39 are electrically connected, respectively. 4° and 41 are hot water temperature detectors for the high temperature water tank 16a and medium temperature water tank 15b, respectively, and the pump 9.
It is electrically connected to the compressor 12.

In the above configuration, when the detected value of the stored hot water temperature detector 40.41 becomes equal to or less than a predetermined value, the pump 9. The compressor 12 is operated to perform a feed water heating operation.

Since the feed water heating cycle on the refrigerant side is the same as in the conventional example, the explanation will be omitted, and the water side will be explained.

Similar to FIG. 2, FIG. 4 shows the relationship between the refrigerant temperature TR and the hot water Tw, with the vertical axis representing the temperature T1 and the horizontal axis representing the heat transfer region M. In the figure, M' is the heat transfer area in the first feed water heating heat exchanger η, and A
" is the heat transfer area in the second feed water heating heat exchanger 23. Water entering the feed water population 3o at a water temperature twi passes through the second feed water heating heat exchanger 23 to a refrigerant two-phase area P and a supercooled liquid area. (In Figure 4, it includes some superheated gas region G, but the amount of heat is small) released from
b, and the remaining part whose flow rate has decreased is further heated by the heat released from the superheated gas region G of the refrigerant in the first water supply heating heat exchanger 22, and reaches the water temperature twn, and is sent from the first tap 31 to the high-temperature water tank. The hot water is circulated to 161L and stored.

Here, the refrigerant inlet temperature tni is 80 to 1000c1 refrigerant U
The condensation temperature tic is about 60 to 66°C, which is the same as the conventional one, but the hot water temperature is controlled by the flow rate control valve 36, 37, so it is the second outlet temperature. tWM is 46~6oOC at sprue 32
1 At the first tap 31, the temperature is 70~so'
c, which makes it possible to raise the temperature by about 16 to 20'C compared to the conventional method.

The attached table shows the heat transfer coefficients on the refrigerant and water sides when a smooth pipe with a passage inner diameter of φ8.6 is used for a heating amount of approximately 4000 单A refrigerant and water. The transmissibility differs widely, and in the superheated gas region, the refrigerant side and the water side also differ widely. This shows that when designing a heat exchanger, it is better to design the superheated gas region and the two-phase region separately, and in the superheated gas region, measures should be taken to improve the heat transfer coefficient on the refrigerant side or increase the heat transfer area. Dedicated heat exchanger In the above embodiment of the present invention, the feed water heating heat exchanger is
Since it is formed by two feed water heating heat exchangers, it is easy to design the heat exchanger for the superheated gas region, and it is possible to obtain a lightweight and compact heat exchanger.

As described above, in the water heater of the present invention, the boiler, the first and the second water supply heating heat exchangers are arranged in series, and the hot water outlet is provided in the water side communication path connecting the water exchanger. The following effects can be obtained.

(1) The amount of water supplied by the first hot water heating heat exchanger is smaller than that of the second hot water heating heat exchanger, and the refrigerant temperature is much higher.
At the tap, hot water can be supplied at a high temperature of 16 to 200 G higher than conventional hot water.

(2) Since medium-temperature hot water can be supplied from the second tap at the same time as high-temperature hot water is supplied, usability is significantly improved.

(3) Since it is formed by two heat exchangers, the first and second feed water heating heat exchangers, the heat exchanger can be designed according to the state of the refrigerant, and it can be made lighter and more compact.

[Brief explanation of the drawings] Figure 1 is a configuration diagram of a conventional water heater, Figure 2 is a diagram of the temperature characteristics of water and refrigerant in a conventional water supply heating heat exchanger, and Figure 3 is a diagram of the temperature characteristics of water and refrigerant in a conventional water supply heating heat exchanger.
FIG. 4 is a block diagram of a water heater according to an embodiment of the present invention, and FIG. 4 is a diagram showing the temperature characteristics of water and refrigerant in the first and second water supply heating heat exchangers of the same device. 9...Pump, 12...Compressor, 16...
...Hot water tank, 16+L ...High temperature water tank, 15b
... Medium temperature water tank, 22 ... First feed water heating heat exchanger, 23 ... Second feed water heating heat exchanger, 31 ...
...First tap, 32...Second tap. Name of agent: Patent attorney Toshio Nakao IT staff: 11 people Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) A first feedwater heating heat exchanger having a water supply side passage heated by heat released due to a phase change in the condensation process of the refrigerant is connected in series to the water supply side passage of the first feedwater heating heat exchanger. a second water supply heating heat exchanger having one water supply side passage, and a hot water outlet is provided in a connecting passage connecting each water supply side passage of the first water supply heating heat exchanger and the second water supply heating heat exchanger; A hot water supply device in which the amount of water supplied in the first water heating heat exchanger is smaller than the amount of water supplied in the second heating heat exchanger. 2. The water heater according to claim 1, wherein the refrigerant in the first water supply heating heat exchanger is in a superheated gas phase, and in the second water supply heating heat exchanger, it is in two phases of gas and liquid.