JP6618748B2 - Method for operating hot water system and method for reconstructing hot water system - Google Patents

Description

The present invention relates to a method for operating a hot water supply system using a heat pump water heater and a method for reconstructing a hot water supply system .

  As shown in FIG. 6, the conventional hot water supply system 100 includes a water supply pipe 110, a hot water storage tank 120, a circulation path 130, and a heat source device 140. Water from the water supply pipe 110 is supplied to the hot water storage tank 120, and the heat source device 140 supplies heat to the hot water storage tank 120 by heating the hot water passing through the circulation path 130. The hot water storage tank 120 is a sealed hot water storage tank and is filled with hot water in a steady state. When hot water in the hot water storage tank 120 is discharged to a hot water supply load by a hot water supply pump (not shown), the same amount of water as the discharged hot water is supplied to the hot water storage tank 120 via the water supply pipe 110. Accordingly, when the temperature of the hot water in the hot water storage tank 120 falls below the set value, the hot water in the hot water storage tank 120 is supplied to the circulation path 130 by the circulation pump P, heated by the heat source device 140, and returned to the hot water storage tank 120.

  In the heat source unit 140, for example, two heavy oil boilers 140A and 140B are arranged in parallel to the hot water storage tank 120. Each of the two heavy oil boilers 140A and 140B performs heat exchange between hot water supplied to the circulation path 130 and hot water heated by heavy oil in the heat exchangers 141A and 141B shown in FIG. For example, while one heavy oil boiler 140A is stopped by inspection or maintenance, it is switched to the other heavy oil boiler 140B.

  Patent Documents 1 and 2 disclose that a heat pump water heater is used as the heat source device 140. In FIG. 1 of Patent Document 1, a circulation path (not shown) is connected to the sealed tank 3 (corresponding to the hot water storage tank 120 in FIG. 6 of the present application), and four heat pump water heaters 2 (this application) are connected to the circulation path. (Corresponding to the heat source device 140 of FIG. 6) is provided in parallel. In FIG. 1 of Patent Document 1, an open tank 5 is added downstream of the sealed tank 3 (corresponding to the hot water storage tank 120 in FIG. 6 of the present application), and hot water is supplied from the open tank 5 to the hot water supply load. ing.

  On the other hand, in patent document 2, it replaces with the enclosed hot water storage tank 120 of FIG. 6 of this application, and the open air hot water storage tank 2 (refer to 0010 of patent document 2) is provided as shown in FIG. . In addition, instead of the water supply pipe 110 in FIG. 6 of the present application, a pipe from the heat source device 100 is connected to the hot water storage tank 2 in FIG. A circulation path (not indicated) is connected to the open-type tank 2 of Patent Document 2, and a heating unit 3 (corresponding to the heat source apparatus 140 in FIG. 6 of the present application) having a heat pump water heater is provided in the circulation path.

JP 2007-205698 A JP 2009-216265 A

  6 of the present application, and any of the hot water supply systems shown in FIG. 1 of Patent Documents 1 and 2, the heat source device 140 shown in FIG. 6) is equivalent to the hot water storage tank 120 shown in FIG. 6 (corresponding to the closed tank 3 in Patent Document 1 and the open tank 2 in Patent Document 2), always keeping the warm water at 60 ° C. to 65 ° C. It is provided to suppress the growth and propagation of miscellaneous bacteria such as Resinella (see Patent Document 1, 0027, Patent Document 2, 0004, and 0028-0029).

  Here, in a hot water supply system installed in a facility such as a hotel or a sports gym that consumes a large amount of hot water, a hot water storage tank 120 shown in FIG. 6 (open tank 5 in Patent Document 1, open tank 2 in Patent Document 2). It is necessary to increase the capacity.

  However, the warm water of the large-capacity hot water storage tank 130 (corresponding to the open tank 2 in Patent Document 2) is retained by the heat retaining operation by the heat source device 140 (corresponding to the heating unit 3 in Patent Document 2) shown in FIG. This is inefficient because the heat dissipation from the hot water storage tank increases as the capacity increases. On the other hand, in Patent Document 1, since the capacity of the closed tank 3 does not need to be increased, there is no problem of inefficiency of the four heat pump water heaters 2, but the reheating device 11 is also provided downstream of the large capacity open tank 5. Need to be placed. That is, in Patent Document 2, heat is maintained using four heat pump water heaters 2 and the closed tank 3 upstream of the large capacity open tank 5, and the reheating device 11 is downstream of the large capacity open tank 5. Must be kept warm.

An object of one embodiment of the present invention is to provide a method of operating a hot water supply system that can efficiently perform hot water supply and heat insulation to a hot water storage tank.
Another aspect of the present invention is to provide a hot water supply system rebuilding method that can realize a hot water supply system capable of efficiently performing hot water supply and heat insulation to a hot water storage tank by adding to existing equipment. And

(1) One aspect of the present invention is
A primary heat source machine that heats the supplied water,
An open-type primary hot water storage tank for storing the hot water supplied from the primary heat source machine;
A secondary hot water storage tank for storing the hot water supplied from the primary hot water storage tank and supplying the hot water to a hot water supply load;
A circulation path connected to the secondary hot water storage tank and circulating the warm water supplied from the secondary hot water storage tank back to the secondary hot water storage tank;
A secondary heat source machine that heats the hot water supplied to the circulation path and keeps the warm water in the secondary hot water storage tank;
Have
The primary heat source machine is a type of heat pump water heater that provides a higher coefficient of performance as the temperature difference in temperature rise is larger,
The hot water temperature of the primary hot water storage tank relates to a hot water supply system in which the temperature of the hot water of the secondary hot water storage tank is higher.

According to one aspect of the present invention, hot water heated by a hot water supply operation (hot water storage operation) of a primary heat source machine is supplied to a primary hot water storage tank having a relatively large capacity regardless of whether or not hot water supply to the hot water storage load side is necessary. Thus, the hot water in the secondary hot water storage tank having a relatively small capacity for supplying hot water to the hot water supply load can be kept warm by performing a heat insulation operation only when the secondary heat source machine is necessary. Moreover, when the primary heat source device is a heat pump water heater using CO ₂ as a refrigerant, for example, the coefficient of performance (COP) increases as the difference between the water supply temperature before heat exchange by the heat pump water heater and the hot water temperature after heat exchange increases. : Coefficient Of Performance) is exceptionally large. Therefore, hot water storage (hot water supply) to the primary hot water storage tank can be efficiently performed.

  (2) In 1 aspect of this invention, the temperature of the warm water of the said primary hot water storage tank can be made higher than the temperature of the warm water of the said secondary hot water storage tank. If it carries out like this, a secondary hot water storage tank can be heated up with the "hot water" by supply of the high temperature water from a primary hot water storage tank. Thereby, the energy loss by the heat insulation driving | operation of a secondary hot water storage tank can be reduced.

  (3) In 1 aspect of this invention, the capacity | capacitance of the said primary hot water storage tank can be made larger than the capacity | capacitance of the said secondary hot water storage tank. In this way, the primary heat source unit performs a hot water storage operation (hot water supply operation) in which the amount of heat is given to the low-temperature supply water and the temperature is raised to a set temperature, for example, 65 ° C., using, for example, a midnight time zone where the electricity rate is low. be able to. The hot water storage operation (hot water supply operation) of the primary heat source machine is a large temperature difference operation compared to the heat insulation operation of the secondary heat source machine. Since the primary heat source machine has a high coefficient of performance in a large temperature difference operation, it can store hot water efficiently.

  (4) In one aspect of the present invention, the secondary hot water storage tank may be a sealed hot water storage tank. The closed hot water storage tank has a temperature distribution from the bottom to the top when the water in the tank cools. If a circulation path for returning the cold water on the bottom side to the top side is provided at the time of reheating, the heat can be efficiently maintained.

  (5) In one mode of the present invention, the primary heat source machine may include a plurality of heat pump water heaters connected in parallel to the primary hot water storage tank. If it carries out like this, according to the capacity | capacitance of a primary hot water storage tank, the rating of a heat pump water heater, etc., the parallel number of heat pump water heaters can be determined, and hot water supply capability can be ensured to the capacity | capacitance of a primary hot water storage tank.

  (6) Another aspect of the present invention is a hot water supply subsystem used in the hot water supply system according to any one of (1) to (5) described above, and a primary heat source machine that converts hot water into hot water. And an open type primary hot water storage tank for storing the hot water supplied from the primary heat source machine.

  Utilizing the existing equipment as a secondary hot water storage tank as a secondary hot water supply system, a circulation path and a secondary heat source machine, connecting the hot water supply subsystem according to another aspect of the present invention to this existing equipment as a primary hot water supply subsystem, A hot water supply system according to one embodiment of the present invention can be constructed.

It is a figure showing the hot-water supply system and hot-water supply subsystem concerning one embodiment of the present invention. It is a figure which shows the air | atmosphere release type primary hot water storage tank. It is a figure which shows a sealed secondary hot water storage tank. FIG. 4 (A) shows a comparative example in which heat insulation operation is performed in the primary hot water supply subsystem, and FIG. 4 (B) is a diagram showing an example in which hot water storage (hot water supply) operation is performed in the primary hot water supply subsystem. It is a Ph diagram of a heat pump. It is a figure which shows the existing equipment (a secondary hot water storage tank, a circulation path, and a secondary heat source machine).

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not always.

1. Hot-water supply system The hot-water supply system 1 which concerns on this embodiment has the primary hot-water supply subsystem 2 and the secondary hot-water supply subsystem 3 as shown in FIG. In the primary hot water supply subsystem 2, a primary heat source device 10 and a primary hot water storage tank 20 are disposed. In the secondary hot water supply subsystem 3, a secondary hot water storage tank 30, a circulation path 40, and a secondary heat source machine 50 are arranged.

The primary heat source device 10 turns the water supplied from the water supply pipe 4 into warm water by a heat pump water heater using CO ₂ as a refrigerant. The primary hot water storage tank 20 is an open-type hot water storage tank that stores hot water supplied from the primary heat source device 10. The secondary hot water storage tank 30 stores the hot water supplied from the primary hot water storage tank 20 and supplies this hot water to the hot water supply load 5. The circulation path 40 is connected to the secondary hot water storage tank 30 and returns the hot water supplied from the secondary hot water storage tank 30 to the secondary hot water storage tank 30 for circulation. The secondary heat source unit 50 heats the hot water supplied from the secondary hot water storage tank 30 to the circulation path 40 to keep the hot water in the secondary hot water storage tank 30 warm.

Here, the primary heat source device 10 is configured by one or a plurality of heat pump water heaters 12. In the present embodiment, for example, three heat pump water heaters 12 are provided in parallel to the primary hot water storage tank 20. In each heat pump water heater 12, CO ₂ gas, which is a refrigerant, absorbs heat in the air and compresses the refrigerant, whereby the temperature of the refrigerant is further increased. Heat exchange is performed between the supplied water and the refrigerant. That is, the supplied water (ordinary temperature) is transferred to the heat of the refrigerant and is heated to a set temperature, for example, 65 ° C. to 75 ° C. The refrigerant is repeatedly used for heat exchange by being circulated.

  The primary hot water storage tank 20 communicates with the atmosphere at a position higher than the upper surface of the hot water, for example, the top wall 22A of the heat insulating wall 22, as shown in FIG. 2, in a normal hot water storage state in which the hot water supplied from the primary heat source device 10 is stored. An open-air type having an opening 24 is used.

  The primary heat source machine 10 that supplies hot water to the primary hot water storage tank 20 is operated as a hot water storage operation or a hot water supply operation. The hot water storage operation (hot water supply operation) is a method in which water supplied at room temperature, for example, 17 ° C. is heated to, for example, 65 ° C. by the primary heat source device 10, and the hot water is supplied to the primary hot water storage tank 20 to store hot water.

The primary hot water storage tank 20 is a hot water storage tank whose water level can be changed, and can store hot water supplied by the hot water storage operation of the primary heat source machine 10 until the water level is full. When the primary hot water storage tank 20 has a sufficient hot water storage capacity or a large amount of hot water is consumed, the primary heat source unit 10 gives heat to a relatively low temperature supply water to a set temperature such as 65 ° C. It is only necessary to keep the temperature raised, and such an operating state is called a hot water storage operation (hot water supply operation). Since the hot water storage operation (hot water supply operation) is a large temperature difference operation as compared with the heat retention operation, the primary heat source device 10 is constituted by, for example, a heat pump water heater 12 using CO ₂ as a refrigerant, as will be described later. Coefficient of performance (COP) is exceptionally high.

  The secondary hot water storage tank 30 stores hot water supplied from the primary hot water storage tank 20 and keeps the temperature warm by the circulation path 40 and the secondary heat source device 50 when the temperature of the hot water decreases. Therefore, as long as the heat retaining function is added, the secondary hot water storage tank 30 may be open to the atmosphere or sealed. In this embodiment, as shown in FIG. 3, the secondary hot water storage tank 30 is a sealed hot water storage tank. The sealed secondary hot water storage tank 30 is filled with warm water of, for example, an average of 60 ° C. in a steady state.

  Unlike the primary heat source device 10 that performs hot water storage operation (hot water supply operation), the secondary heat source device 50 is operated for heat insulation. Here, the hot water generally stored in the hot water storage tank is naturally radiated even if the tank wall is insulated. Therefore, the hot water stored in the hot water storage tank has a temperature distribution from the bottom to the top of the tank, and the bottom side has a low temperature and the top side has a high temperature. The heat insulation operation refers to, for example, hot water of 60 ° C. on the bottom side of the secondary hot water storage tank 30 being drawn into the circulation path 40 and heated to, for example, 70 ° C. by the secondary heat source device 50, and the top side of the secondary hot water storage tank 30. It is driving to return to. The heat insulation operation is a small temperature difference operation, but it is not always necessary to perform the operation. For example, the temperature of the hot water at the bottom side of the secondary hot water storage tank 30 is measured with a sensor, and the heat insulation operation is performed only when the temperature drops to 60 ° C., for example. do it. As described above, in order to perform the heat insulation operation only when necessary, the pressurized water supply pump P and the valve V are provided in the pipe connecting the primary hot water storage tank 20 and the secondary hot water storage tank 30. By switching the valve V, water from the water supply pipe 4 can be supplied to the secondary hot water storage tank 30.

  For example, as shown in FIG. 3, the sealed secondary hot water storage tank 30 is provided with a supply port 34 </ b> A to which hot water from the primary hot water storage tank 20 is supplied on the bottom side of the heat insulating wall 32 that stores hot water with full water. A discharge port 34 </ b> B for discharging hot water to the hot water supply load 5 is provided on the top side of 32. Furthermore, in order to efficiently perform the above-described heat insulation operation, the inlet 40A of the circulation path 40 is connected to the bottom side of the hermetic secondary hot water storage tank 30 and the outlet 40B of the circulation path 40 as shown in FIG. Is connected to the top side of the secondary hot water storage tank 30.

  The method of the secondary heat source machine 50 is not particularly limited, and in the present embodiment, for example, two heavy oil boilers 50 </ b> A and 50 </ b> B are arranged in parallel to the secondary hot water storage tank 30. Each of the two heavy oil boilers 50A and 50B performs heat exchange between hot water supplied to the circulation path 40 and hot water heated by heavy oil in the heat exchangers 51A and 51B shown in FIG. For example, while one heavy oil boiler 50A is stopped by inspection or maintenance, it is switched to the other heavy oil boiler 50B.

  In the hot water supply system 1 shown in FIG. 1, the hot water storage tank 120, the circulation path 130, and the heat source device 140 as the existing equipment 100 shown in FIG. The circulation path 40 and the secondary heat source machine 50) may be used. That is, the hot water supply system 1 may be constructed by adding the hot water supply subsystem 2 including the primary heat source device 10 and the primary hot water storage tank 20 to the existing facility shown in FIG. At this time, one of the two boilers 50A and 50B constituting the secondary heat source device 50 shown in FIG. .

2. Operation of hot water supply system 2.1. Significance of the presence of the primary hot water supply subsystem The open primary hot water storage tank 20 of the primary hot water supply subsystem 2 is a hot water storage tank whose water level can be changed. Can be saved. Here, the temperature of the open-type primary hot water storage tank 20 of the primary hot water supply subsystem 2 can be made higher than the temperature of the secondary hot water storage tank 30 of the secondary hot water supply subsystem 3. If it carries out like this, a secondary hot water storage tank can be heated up by the "hot water" by the supply of the high temperature water from a primary hot water storage tank. Thereby, the energy loss by the heat insulation driving | operation of a secondary hot water storage tank can be reduced.

Further, the capacity of the open primary hot water storage tank 20 of the primary hot water supply subsystem 2 can be made larger than the capacity of the secondary hot water storage tank 30 of the secondary hot water supply subsystem 3. As a result, the primary heat source unit performs a hot water storage operation (hot water supply operation) in which the amount of heat is given to the low-temperature supply water and the temperature is raised to a set temperature, for example, 65 ° C., using a late-night time period in which the electricity bill is inexpensive. Can do.
For example, the primary hot water storage tank 20 can have a capacity for storing a maximum amount of hot water consumed in a day, and it is preferable to secure a large capacity within the constraints of installation space and load resistance. In the present embodiment, it is assumed that the hot water supply system 1 is disposed in a facility that consumes a large amount of hot water, such as a hotel or a sports gym, and the capacity of the primary hot water storage tank 20 can be stored, for example, 4 t.

  Hot water is supplied to the primary hot water storage tank 20 from the heat pump type primary heat source unit 10 preferably at a time when the electricity bill at midnight is cheap. Since the consumption of hot water is low at midnight, it is also preferable in that the sudden heat demand is small. However, the operation time of the primary heat source machine 10 may be other than midnight.

  The significance of the presence of the primary hot water supply subsystem 2 is that the primary heat source unit 10 continues the above-described hot water supply operation (hot water storage operation), which is a high temperature difference operation with a high coefficient of performance, regardless of whether or not hot water supply to the hot water supply load 5 is necessary. More preferably, it is to continue the implementation at midnight when the electricity bill is cheap. Furthermore, hot water can be supplied to the open-type, preferably large-capacity primary hot water storage tank 20 as “hot water”. The primary hot water storage tank 20 of the primary hot water supply subsystem 2 is an open type that is separated from the hot water supply load 5 and can change the water level in the tank, and the primary heat source unit 10 has a higher coefficient of performance as the temperature difference in temperature rise increases. This is because the heat pump water heater of the type that can be obtained.

2.2. Significance of Secondary Hot Water Subsystem Subsidiary Significance of the secondary hot water subsystem 3 is that the primary hot water subsystem 2 eliminates the need to insulate the large capacity primary hot water storage tank 20 inefficiently. In the secondary hot water supply subsystem 3, an amount of hot water sufficient to supply hot water to the hot water supply load 5 is stored in the secondary hot water storage tank 30 from the primary hot water storage tank 20. Only when the hot water supply to the hot water supply load 5 is stopped for a relatively long time, the secondary heat source machine 50 is operated, and the hot water in the secondary hot water storage tank 30 having a relatively small capacity is efficiently supplied. Can keep warm.

2.3. Comparison of hot water supply operation and heat insulation operation in the primary hot water supply system Hereinafter, the hot water supply operation and the heat insulation operation will be compared using quantitative data. Consider a case where 4.0 t of feed water having an incoming water temperature of 17 ° C. is heated to 65 ° C. and supplied to a hot water supply load. FIG. 4 (A) shows a comparative example in which the closed type hot water storage tank is used and “heat insulation operation” of the heat pump water heater is performed, and FIG. 4 (B) is an open type hot water tank in which “hot water storage operation” The example of the primary side hot-water supply subsystem 2 of this embodiment performed by "is shown.

  Here, in the heat insulation operation of the comparative example shown in FIG. 4A, the temperature difference before and after the temperature rise in the heat pump water heater is about 10 ° C. On the other hand, in the hot water storage operation of the embodiment shown in FIG. 4B, the temperature difference before and after the temperature rise in the heat pump water heater is 48 ° C. (= 65 ° C.−17 ° C.).

The required power consumption is compared for these two examples. As the heat pump water heater using CO ₂ as a refrigerant used in FIGS. 4A and 4B, it was assumed that Mitsubishi Heavy Industries, Ltd. ESA30-5 having two operation modes was used. The heating performance of ESA30-5 manufactured by Mitsubishi Heavy Industries, Ltd. is as follows, referring to the website of Mitsubishi Heavy Industries, Ltd.
(A) Thermal insulation operation Output (heating capacity): 13.0 [kW]
Input (power consumption): 8.5 [kW]
Coefficient of performance COP: 13.0 [kW] ÷ 8.5 [kW] = 1.529
(B) Hot water storage operation Output (heating capacity): 30.0 [kW]
Input (power consumption): 6.98 [kW]
Coefficient of performance COP: 30.0 [kW] ÷ 6.98 [kW] = 4.298

Here, for example, in a heat pump water heater using CO ₂ as a refrigerant, a coefficient of performance COP is higher in a hot water supply operation (hot water storage operation) having a large temperature difference than in a heat retention operation having a small temperature difference. This is different from a general heat pump.

Generally, the heat pump repeats the evaporation process A, the compression process B, the condensation process C, and the expansion process D shown in FIG. The heat pump carries heat from the low temperature part to the high temperature part by performing this series of cycles. The temperature in the low temperature part is T1, the temperature in the high temperature part is T2, the amount of heat absorbed by the working medium in the evaporation step A is Q1, the amount of heat released from the working medium in the condensation step C is Q2, and the compression in the compression step B If the input energy from the machine is W, Q2 = Q1 + W, and generally, the coefficient of performance COP is obtained by the following equation.
COP = Q2 / W
= Q2 / (Q2-Q1)
= T2 / (T2-T1) (1)

  From this equation (1), it can be seen that the smaller the temperature difference (T2-T1) between the high temperature part and the low temperature part, the better the coefficient of performance. That is, in general, since the efficiency is not good when the temperature difference is large, the heat pump is not suitable for an application having a large temperature difference.

However, the equation (1) is not applied to the heat pump water heater 12 using CO ₂ as a refrigerant, and as described above, the coefficient of performance COP is higher when the temperature difference (T2−T1) is larger.

The amount of heat required to raise the temperature of feed water 4.00 [t] at an incoming water temperature of 17.0 [° C.] to 65.0 [° C.] is as follows.
4.00 [t] x 1000 [l / t] x (65.0 [° C] -17.0 [° C]) = 192000 [kcal] (2)

When the heat supply shown in equation (2) is performed in the “heat insulation operation” of the heat pump water heater using the sealed hot water storage tank shown in FIG. 4 (A), the coefficient of performance COP is 1.529 in the heat insulation operation. Considering that the required power consumption is 1.000 [cal] = 4.18605 [J] and 1.000 [Wh] = 3600 [J],
192000 [kcal] ÷ 1.529 × 4.18605 [kJ / kcal] ÷ 3600 [kJ / kWh] = 146.0 [kWh]… (3)
It becomes.

When performing the heat supply shown in equation (2) in the “hot water storage operation” of the heat pump water heater using the open-type hot water storage tank shown in FIG. 4B, the coefficient of performance COP is 4.298 in the hot water storage operation. Power consumption is
192000 [kcal] ÷ 4.298 × 4.18605 [kJ / kcal] ÷ 3600 [kJ / kWh] ＝ 51.94 [kWh]… (4)
It becomes.

  As is clear from the comparison of equations (3) and (4), the power consumption required for the same heat supply shown in equation (2) is small at 51.94 [kWh] during hot water storage operation. In the heat insulation operation of the example, it increases to 146.0 [kWh]. Therefore, it turns out that power consumption can be reduced by using the hot-water supply subsystem 2 of this embodiment.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention.

1 hot water supply system, 2 primary hot water supply subsystem, 3 secondary hot water supply subsystem, 10 primary heat source machine, heat pump water heater using 12 CO ₂ as refrigerant, 20 primary hot water storage tank (open type), 30 secondary hot water storage tank, 40 circulation Road, 50 Secondary heat source machine

Claims (6)

A primary heat source machine that heats the supplied water,
An open-type primary hot water storage tank for storing the hot water supplied from the primary heat source machine;
A secondary hot water storage tank for storing the hot water supplied from the primary hot water storage tank and supplying the hot water to a hot water supply load;
A circulation path connected to the secondary hot water storage tank and circulating the warm water supplied from the secondary hot water storage tank back to the secondary hot water storage tank;
A secondary heat source machine that heats the hot water supplied to the circulation path to keep the hot water in the secondary hot water storage tank warm when the hot water in the secondary hot water storage tank becomes a predetermined temperature or lower ;
Have
The primary heat source machine is a method of operating a hot water supply system that is a heat pump water heater of a type that provides a higher coefficient of performance as the temperature difference in temperature rise is larger ,
In the primary heat source machine, a hot water storage operation is performed in which normal temperature water to be supplied is heated to a hot water of 65 ° C. to 75 ° C. higher than the temperature of the hot water in the secondary hot water storage tank and stored in the primary hot water storage tank. The operation method of the hot water supply system is characterized in that the heat insulation operation having a smaller temperature difference in temperature rise than the hot water storage operation is not performed . In the operation method of the hot water supply system according to claim 1,
An operation method for a hot water supply system , wherein the hot water in the secondary hot water storage tank is heated by supplying hot water from the primary hot water storage tank to the secondary hot water storage tank . In the operation method of the hot water supply system according to claim 1 or 2,
An operation method of a hot water supply system , wherein hot water is stored in the primary hot water storage tank having a capacity larger than that of the secondary hot water storage tank by the hot water storage operation . In the operation method of the hot water supply system according to any one of claims 1 to 3,
The secondary hot water storage tank, Ri sealed hot water storage tank der,
The hot water of the primary hot water storage tank is supplied to the bottom side of the secondary hot water storage tank, the hot water of the secondary hot water storage tank is supplied from the top side of the secondary hot water storage tank to the hot water supply load,
The secondary heat source device keeps warm water flowing through the circulation path having an inlet connected to a bottom side of the secondary hot water storage tank and an outlet connected to a top side of the secondary hot water storage tank. The operation method of the hot water supply system. In the operation method of the hot water supply system according to any one of claims 1 to 4,
Wherein as a primary heat source unit, a method of operating a hot water supply system, which comprises using a plurality of heat pump water heater which is connected in parallel with the primary hot water storage tank. In a method of reconstructing a hot water supply system by adding a primary hot water supply subsystem to an existing system used as a secondary hot water supply subsystem,
A primary heat source device that warms the supplied water, an open-type primary hot water storage tank that stores the hot water supplied from the primary heat source device, and a primary pump that supplies the hot water in the primary hot water storage tank. Increase the primary hot water supply subsystem,
The secondary hot water supply subsystem, which is the existing system,
The secondary hot water supply subsystem is
A secondary hot water storage tank,
A secondary hot water storage tank for storing hot water supplied to the hot water supply load;
A circulation path connected to the secondary hot water storage tank and circulating the warm water supplied from the secondary hot water storage tank back to the secondary hot water storage tank;
A secondary pump provided in the circulation path;
A secondary heat source machine that heats the hot water supplied to the circulation path when the hot water in the secondary hot water storage tank becomes a predetermined temperature or less, and keeps the hot water in the secondary hot water storage tank;
Have
The secondary hot water storage tank is connected to the primary hot water storage tank so as to store the hot water supplied from the primary hot water storage tank,
The capacity of the primary hot water storage tank is set larger than the capacity of the existing secondary hot water storage tank,
The primary heat source machine is a heat pump water heater of a type in which a higher coefficient of performance is obtained as the temperature difference of the temperature rise is larger, and the normal temperature water supplied is higher than the temperature of the hot water in the secondary hot water storage tank 65 A hot water storage system for reconstructing a hot water supply system, wherein a hot water storage operation for heating to warm water of from C to 75C is performed, and a heat insulation operation in which a temperature difference in temperature rise is smaller than that of the hot water storage operation is not performed .

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