Cooling and heating device

[Object]The purpose is to provide a cooling and heating device.[Solution]This cooling and heating device includes: a fuel cell device including a fuel cell; a heating unit which utilizes the heat of exhaust gas discharged from the fuel cell; a thermoacoustic cooler (14) including a cooling unit which performs a cooling function with use of the heat of the exhaust gas discharged from the fuel cell; and an exhaust gas switching unit (25) which allows the exhaust gas discharged from the fuel cell to be supplied to at least one of the thermoacoustic cooler (14) and the heating unit, whereby there can be provided a cooling and heating device which effectively utilizes the exhaust gas of a fuel cell.

TECHNICAL FIELD

The present invention relates to a cooling and heating device that includes a combination of a thermoacoustic cooler and a fuel cell device.

BACKGROUND ART

In recent years, there have been proposed, as next generation energy sources, various fuel cell modules that include fuel cells capable of generating power using a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air) in a housing, and various fuel cell devices that include fuel cell modules in an exterior casing (refer to Patent Document 1, for example).

Further, in recent years, there have been proposed thermoacoustic refrigerators having a refrigerating function based on thermoacoustic energy (refer to Patent Document 2, for example).

CITATION LIST

Patent Literature

Patent Document 2: Japanese Unexamined Patent Application Publication No. 2013-117325A

SUMMARY OF INVENTION

Technical Problem

While various devices such as fuel cell devices and thermoacoustic refrigerators have been developed as next generation energy sources as described above, there is still considerable room for investigating the development of novel applications that combine these devices.

Therefore, an object of the present invention is to provide a novel application that combines a thermoacoustic cooler that uses thermoacoustic energy and a fuel cell device.

Solution to Problem

A cooling and heating device of the present invention includes a fuel cell device including a fuel cell; a heating unit configured to utilize the heat of exhaust gas discharged from the fuel cell; a thermoacoustic cooler including a cooling unit configured to perform a cooling function with use of the heat of the exhaust gas discharged from the fuel cell; and an exhaust gas switching unit that allows the exhaust gas discharged from the fuel cell to be supplied to at least one of the thermoacoustic cooler and the heating unit.

Advantageous Effects of Invention

The cooling and heating device of the present invention switches a supply destination of the exhaust gas discharged from the fuel cell to at least one of the heating unit and the thermoacoustic cooler to selectively utilize one of the heating function of the heating unit and the cooling function of the cooling unit, thereby making it possible to achieve an efficient cooling and heating device.

DESCRIPTION OF EMBODIMENTS

FIG. 1is a configuration diagram illustrating an example of a configuration of the cooling and heating device of the present embodiment,FIG. 2is a configuration diagram illustrating another example of the configuration of the cooling and heating device of the present embodiment,FIG. 3is an exterior perspective view of an example of the fuel cell module illustrated inFIGS. 1 and 2, andFIG. 4is a cross-sectional view of the fuel cell module illustrated inFIG. 3. Note thatFIG. 1illustrates a cooling function,FIG. 2illustrates a heating function, and the configuration of each device is the same. Thus, in the following descriptions of the configurations,FIG. 1will be mainly used for explanation.

The cooling and heating device illustrated inFIG. 1includes a power generating unit as an example of a fuel cell device, and a thermoacoustic cooler that produces thermoacoustic energy using exhaust gas discharged from the power generating unit and performs cooling (refrigeration) using the produced thermoacoustic energy. Note that in the subsequent figures, the same reference numerals are used for the same components.

The power generating unit as the fuel cell device illustrated inFIG. 1includes a cell stack2that includes a plurality of fuel cells, a raw fuel supplying means4for supplying a raw fuel such as a city gas, an oxygen-containing gas supplying means5for supplying an oxygen-containing gas to the fuel cells constituting the cell stack2, and a reformer3that performs steam reforming on the raw fuel using steam. Note that, while described later, a fuel cell module1(hereinafter, may be abbreviated as “module1”) includes the cell stack2and the reformer3in a housing. InFIG. 1, the module1is surrounded by a long dashed double-short dashed line. Further, while not illustrated in the figures, an ignition device for combusting the fuel gas not used in power generation is provided in the module1.

The power generating unit illustrated inFIG. 1includes a heat exchanger6that subjects exhaust gas (exhaust heat) to heat exchange to decrease the temperature of the exhaust gas, the exhaust gas being generated through the power generation in the fuel cells that constitute the cell stack2. In the present embodiment, while described in detail later, the heat exchanger6functions as a heating unit, and therefore the heating unit is described as the heat exchanger6in the following descriptions. The power generating unit illustrated inFIG. 1includes further a condensed water treatment device7for turning condensed water obtained by the condensation of moisture contained in the exhaust gas into pure water, and a water tank8for storing the water (pure water) treated by the condensed water treatment device7. The water tank8and the heat exchanger6are connected through a condensed water supply pipe9. Further, depending on the quality of the condensed water generated by heat exchange in the heat exchanger6, the condensed water treatment device7may not be provided. Furthermore, when the condensed water treatment device7is capable of storing water, the water tank8may not be provided.

The water stored in the water tank8is supplied to the reformer3by a water pump11provided in a water supply pipe10that connects the water tank8and the reformer3.

Furthermore, the power generating unit illustrated inFIG. 1includes a supply power regulating unit (power conditioner)12that converts DC power generated in the module1into AC power and regulates the amount of converted electricity to be supplied to an external load, and a controller13that controls the operation of various devices. Each of these devices constituting the power generating unit is housed in an exterior casing, which forms a simple fuel cell device that can be easily installed.

The following describes a thermoacoustic cooler14. The thermoacoustic cooler14includes a prime mover15, a cooler16, and a connecting pipe17that connects the prime mover15and the cooler16. Note that the prime mover15, the cooler16, and the connecting pipe17are filled with a gas such as a helium gas. Further, heat accumulators18,19are respectively disposed in the prime mover15and the cooler16. One side of the heat accumulator18of the prime mover15serves as a high-temperature portion22(upper side inFIG. 1) while the other side serves as a low-temperature portion20(lower side inFIG. 1). Thermoacoustic energy (sound waves) is produced by the temperature gradient between the two.

InFIG. 1, although described later, the prime mover15is configured to allow the exhaust gas discharged from the module1to flow around the high-temperature portion22of the heat accumulator18. While, on the other hand, nothing is provided around the low-temperature portion20inFIG. 1, in order to produce thermoacoustic energy more efficiently, the prime mover15may be configured to allow a low-temperature refrigerant (such as tap water) to flow around the low-temperature portion20. The high-temperature portion22, the low-temperature portion20, and the heat accumulator18form a thermoacoustic energy producing unit. This thermoacoustic energy producing unit is indicated by the dashed line inFIG. 1.

The thermoacoustic energy produced in the thermoacoustic energy producing unit resonates upon flowing through the prime mover15and the connecting pipe17, and is transmitted to the cooler16. In the cooler16, the thermoacoustic energy is converted into thermal energy. Then, a fluid is made to flow to a high-temperature portion23(upper side inFIG. 1) on one side of the heat accumulator19. This causes an endothermic reaction to occur in a low-temperature portion21(lower side inFIG. 1) on the other side of the heat accumulator19, and decreases the temperature. As a result, a cooling function is imparted to the cooler16. That is, the heat accumulator19, the high-temperature portion23, and the low-temperature portion21form a cooling unit. This cooling unit is indicated by the dashed line inFIG. 1.

Note that, in the cooling unit, the high-temperature portion23only needs to be higher in temperature than the low-temperature portion21, and not high in temperature in the general sense. Specifically, decreasing the temperature of the high-temperature portion23decreases the temperature of the low-temperature portion21even further, thereby imparting a cooling function as well as a refrigerating function to the cooling unit. In other words, the cooling unit has the function as a refrigerating unit. Thus, while inFIG. 1a second piping24described later is provided so that a second fluid that flows through this second piping24flows around the low-temperature portion21and then flows around the high-temperature portion23, the second piping24need not necessarily be provided around the high-temperature portion23.

Further, an exhaust gas switching unit25is provided for allowing the exhaust gas discharged from the module1to flow into at least one of the heat exchanger6and the thermoacoustic cooler14. The provision of the exhaust gas switching unit25makes it possible to allow the exhaust gas to suitably flow into the heat exchanger6or the thermoacoustic cooler14as needed, and thus provide a heating effect and a cooling effect.

Thus, during hot periods such as summer, it is possible to make the exhaust gas discharged from the module1flow into the thermoacoustic cooler14, and then utilize the second fluid cooled by the cooling unit21to provide a cooling function. Further, during cold periods such as winter, it is possible to make the exhaust gas discharged from the module1flow into the heat exchanger6, and then utilize the first fluid heated by the heat exchanger6to provide a heating function. This makes it possible to provide an efficient cooling and heating device.

Note that whileFIGS. 1 and 2illustrate a common house as an example of a cooling/heating target area, the target area is not limited thereto. The cooling/heating target area is not particularly limited as long as the area requires air conditioning, such as an architectural structure including a building, an aircraft, or a boat or ship.

Furthermore,FIGS. 1 and 2illustrate an example in which circulation piping26is provided under the floor of this cooling/heating target area, and first piping30through which the first fluid flows, and the second piping24through which the second fluid flows are connected to this circulation piping26. The first piping30is connected to the heat exchanger6and the second piping24is provided around the cooling unit. Note that one end of the first piping30and one end of the second piping24are connected to the circulation piping26via a first switching unit27, and the other end of the first piping30and the other end of the second piping24are connected to the circulation piping26via a second switching unit28. Thus, the controller13allows the first fluid or the second fluid to flow through the circulation piping26by controlling the first switching unit27and the second switching unit28, making it possible to effectively function as a cooling and heating device.

However, because it is only necessary to provide a cooling and heating function in the cooling/heating target area, the first piping30and the second piping24may each have a circulation piping function as individual piping or, for example, may each be provided with an open end structure so that the first fluid that flows through the first piping30and the second fluid that flows through the second piping24, or the air or the like heated and cooled by these fluids, are directly supplied to the cooling/heating target area. In this case, the circulation piping is not required. Incidentally, in this case, a blower is preferably attached to one end side of each piping to supply air to the first piping30and the second piping24.

The following describes an operation method of the cooling and heating device illustrated inFIGS. 1 and 2. At startup of the fuel cell device, the controller13activates the raw fuel supplying means4, the oxygen-containing gas supplying means5, the water pump11, and the ignition device. At this time, the temperature of the module1is low, and thus power is not generated in the fuel cells and a reformation reaction is not performed in the reformer3. The fuel gas supplied by the raw fuel supplying means4that has not been used in power generation is combusted almost in its entirety, and the combustion heat increases the temperatures of the module1and the reformer3. When the temperature of the reformer3reaches a temperature that allows steam reforming, the reformer3performs steam reforming and a fuel gas which is a hydrogen-containing gas required for power generation in the fuel cells is produced. Note that, once the reformer3reaches a temperature that allows steam reforming, the controller13may also perform control so as to activate the water pump11. When the fuel cells reach a temperature that allows power generation to start, the fuel cells start generating power using the fuel gas produced in the reformer3and the oxygen-containing gas supplied by the oxygen-containing gas supplying means5. The electricity generated in the cell stack2is converted to AC in the supply power regulating unit12and then supplied to an external load.

Note that, after power generation has started in the fuel cells, the controller13controls the operation of the raw fuel supplying means4, the oxygen-containing gas supplying means5, the water pump11, and the like on the basis of a fuel utilization rate (Uf), an air utilization rate (Ua), and a steam to carbon (S/C) ratio set in advance in order to efficiently operate the fuel cell device. The S/C is a molar ratio of the water and the carbon in the fuel under the steam reforming performed by the reformer3. The fuel utilization rate is a value obtained by dividing the amount of fuel gas used in power generation by the amount of fuel gas (raw fuel) supplied by the raw fuel supplying means4, and the air utilization rate is a value obtained by dividing the amount of air used in power generation by the amount of air supplied by the oxygen-containing gas supplying means5.

The exhaust gas produced in association with the operation of the cell stack2is made to flow into at least one of the heat exchanger6and the thermoacoustic cooler14by the exhaust gas switching unit25. Whether the exhaust gas is made to flow into the heat exchanger6or the thermoacoustic cooler14can be set by the user or automatically switched.

For example, a cooling and heating switch is provided in the cooling/heating target area (the switch including shutdown as well) and, when the user switches the switch to utilize cooling or when cooling is automatically run when a predetermined condition is satisfied, the controller13controls the exhaust gas switching unit25so that at least a portion (preferably all) of the exhaust gas discharged from the module1flows into the thermoacoustic cooler14. The exhaust gas that has flowed toward the thermoacoustic cooler14flows through the high-temperature portion22that constitutes the thermoacoustic energy producing unit in the prime mover15of the thermoacoustic cooler14. Specifically, piping (a flow path) through which the exhaust gas discharged from the module1flows is provided so as to surround the one side (high-temperature portion22) of the piping having the heat accumulator18disposed therein. With such a configuration, the exhaust gas flows through the high-temperature portion22of the thermoacoustic energy producing unit. Similarly, in the following descriptions, each piping is disposed so as to surround the piping of the thermoacoustic cooler14, and configured so that each fluid flows through each area of the thermoacoustic cooler14.

As a result, a temperature gradient is produced between the one side and the other side of the heat accumulator18, making it possible to generate thermoacoustic energy. Note that the low-temperature portion20as the thermoacoustic energy producing unit can produce thermoacoustic energy more efficiently when the difference in temperature between the low-temperature portion20and the high-temperature portion22increases, and therefore tap water having a room temperature or the like may be supplied to the low-temperature portion20, for example.

In this case, the controller13controls the first switching unit27and the second switching unit28so that the second fluid (water, air, or the like) that flows through the second piping24flows through the circulation piping26. That is, the second fluid that flows through the second piping24is cooled while flowing through the low-temperature portion21of the cooling unit20, and the cooled second fluid flows through the circulation piping26via the high-temperature portion23of the cooling unit20, thereby cooling the cooling/heating target area and providing a cooling function. Note that the second piping24is configured to allow the second fluid that has flowed through the low-temperature portion21of the cooling unit to flow through the high-temperature portion23, making it possible to further enhance the cooling function of the cooling unit. Further, the amount (flow rate) of the second fluid that flows through the second piping24and the circulation piping26can be regulated as appropriate by controlling a pump31provided between the first switching unit27and the second switching unit28.

Further,FIGS. 1 and 2illustrate an example in which a temperature sensor29is provided in the cooling/heating target area. For example, the controller13may perform control so that the first switching unit27and the second switching unit28are automatically switched to allow the second fluid to flow through the circulation piping26, when the temperature sensor29satisfies a suitably set first condition (a temperature of at least 25° C. continuing for at least one hour, for example). Note that whileFIGS. 1 and 2illustrate an example in which the temperature sensor29is provided in the cooling/heating target area, the location in which the temperature sensor29is provided is not limited thereto, and the temperature sensor29may be disposed outside the cooling/heating target area to measure the temperature of an outside air.

On the other hand, when the user changes the switch to utilize heating or when heating is automatically run when a predetermined condition is satisfied, the controller13controls the exhaust gas switching unit25so that at least a portion (preferably all) of the exhaust gas discharged from the module1flows into the heat exchanger6serving as the heating unit. The exhaust gas that has flowed toward the heat exchanger6exchange heat with the first fluid (water, air, or the like) that flows through the first piping30connected to the heat exchanger6, heating the first fluid.

Then, the controller13controls the first switching unit27and the second switching unit28so that the first fluid that flows through the first piping30flows through the circulation piping26. That is, the first fluid that flows through the first piping30is heated while flowing through the heat exchanger6, and the heated first fluid flows through the circulation piping26, thereby heating the cooling/heating target area and providing a heating function. Further, the amount (flow rate) of the first fluid that flows through the first piping30and the circulation piping26can be suitably regulated by controlling the pump31provided between the first switching unit27and the second switching unit28.

Incidentally, to automatically start the heating function on the basis of the temperature sensor29provided in the cooling/heating target area, the controller13may perform control so that the first switching unit27and the second switching unit28are automatically switched to allow the first fluid to flow through the circulation piping26, when the temperature sensor29satisfies a suitably set second condition (a temperature of at least 10° C. continuing for at least one hour, for example).

The adoption of such an operation method as described above results in the development of a novel application that combines the fuel cell device and the thermoacoustic cooler14, making it possible to achieve an efficient cooling and heating device.

Note that, for example, when the user turns off the cooling and heating switch, or when the temperature measured by the temperature sensor does not satisfy the first and second condition (a temperature of at least 10° C. and less than 25° C. continuing for at least one hour, for example), the controller13may control the exhaust gas switching unit25so that the exhaust gas flow as is into the thermoacoustic cooler14in order to discharge the exhaust gas outside. In this case, the controller13preferably stops the pump31as well. Note that the first condition and the second condition may be set as appropriate.

On the other hand, when water for steam reforming in the reformer3is to be produced using the heat exchanger6, the controller13can also control the operation of the exhaust gas switching unit25and the pump31so that condensed water is obtained in amounts as necessary. However, the operation of the pump31is preferably suitably controlled so that a large amount of first fluid does not flow through the circulation piping26.

Incidentally, in the cooling and heating device illustrated inFIGS. 1 and 2, solid oxide fuel cells (cell stack2) are used as the fuel cells, and thus the heat of the exhaust gas discharged from the module1becomes extremely high in temperature. Using such exhaust gas makes it possible to efficiently produce the first fluid heated by the heat exchanger6and the second fluid cooled by the thermoacoustic cooler14.

Next, the fuel cell device of the present embodiment will be described.

FIG. 3is an exterior perspective view of an example of a module in a fuel cell device constituting the cooling and heating device of the present embodiment, andFIG. 4is a cross-sectional view ofFIG. 3.

The module1illustrated inFIG. 3includes two cell stacks2and a cell stack device40housed in a housing34. In each of the cell stacks2, cylinder-shaped fuel cells32are arranged uprightly in a row, each including a fuel gas flow path (not illustrated) through which a fuel gas flows; the fuel cells32adjacent to each other are electrically connected in series via a current collection member (not illustrated inFIG. 3); and a lower end of each of the fuel cells32is fixed to a manifold33by an insulative bonding material (not illustrated) such as a glass sealing material. In the cell stack device40, the reformers3for producing a fuel gas to be supplied to the fuel cells32are disposed above each of the cell stacks2. At both end portions of each of the cell stacks2, there is disposed an electrically conductive member that includes an electricity drawing unit for collecting electricity generated by the power generation in the cell stack2(the fuel cells32) and drawing the electricity to the outside (not illustrated). The cell stack device40is thus configured with each of the members described above. Note thatFIG. 3illustrates an example in which the cell stack device40includes two cell stacks2. However, the number of cell stacks may be changed as appropriate; for example, the cell stack device40may include only one cell stack2.

Further, the examples of the fuel cells32illustrated inFIG. 3are hollow flat plate-shaped fuel cells that each include a fuel gas path that allows fuel gas to flow through the fuel cells in the lengthwise direction thereof. The fuel cells32are solid oxide fuel cells that each include a fuel electrode layer, a solid electrolyte layer, and an oxygen electrode layer stacked in that order on a surface of a support body that includes the fuel gas path. Note that oxygen-containing gas flows between the fuel cells32.

Further, in the fuel cell device of the present embodiment, the fuel cells32may be solid oxide fuel cells, and flat plate shaped or cylindrical shaped, for example. In addition, the shape of the housing34may also be changed as appropriate.

Moreover, the reformer3illustrated inFIG. 3reforms a raw fuel such as natural gas or kerosene supplied via a raw fuel supply pipe39to produce a fuel gas. It is preferable that the reformer3be capable of performing steam reforming which has an efficient reforming reaction. The reformer3includes a vaporizing unit36that vaporizes water and a reforming unit37that has a reforming catalyst (not illustrated) for reforming the raw fuel into fuel gas disposed therein. Then, the fuel gas produced in the reformer3is supplied to the manifold33via a fuel gas leading-out pipe38. The fuel gas is then supplied via the manifold33to the fuel gas paths formed inside the fuel cells32.

Moreover,FIG. 3illustrates the cell stack device40housed in the housing34, with the cell stack device40removed rearward and a portion of the housing34(front and back surfaces) removed. Here, in the module1illustrated inFIG. 3, the cell stack device40can be slid and housed in the housing34.

Note that an oxygen-containing gas leading-in member35is disposed in the interior of the housing34, between the cell stacks2arranged side by side on the manifold33, so that the oxygen-containing gas flows along the sides of the fuel cells32, from a lower end portion toward an upper end portion.

As illustrated inFIG. 4, the housing34of the module1has a two-layer structure that includes an inner wall41and an outer wall42. The outer wall42forms the outer frame of the housing34, and the inner wall41forms a power generation chamber43that houses the cell stack device40. Furthermore, in the housing34, the space between the inner wall41and the outer wall42forms an oxygen-containing gas flow path44through which oxygen-containing gas flows toward the fuel cells32.

Here, the oxygen-containing gas leading-in member35is inserted from an upper portion of the housing34, passing through the inner wall41, and fixed. The oxygen-containing gas leading-in member35includes, on an upper side, an oxygen-containing gas inflow opening (not illustrated) through which the oxygen-containing gas flows, and flanges45; and, on a lower side, an oxygen-containing gas outflow opening46through which the oxygen-containing gas flows toward a lower end portion of each of the fuel cells32. Moreover, a thermal insulating member47is arranged between each flange45and the inner wall41.

Note that while the oxygen-containing gas leading-in member35is disposed so as to be positioned between the two cell stacks2arranged side by side in the interior of the housing34in theFIG. 4, the number of the cell stacks2may be changed as appropriate. For example, when the housing34houses only one cell stack2, two oxygen-containing gas leading-in members35may be provided and disposed so as to sandwich the cell stack2from both side surface sides.

Moreover, the thermal insulating members47may also be formed inside the power generation chamber43as appropriate in order to maintain a high temperature inside the module1, which prevents a decrease in the temperature of the fuel cells32(cell stacks2) and a decrease in power output that result from excessive radiation of heat from the inside of the module1.

It is preferable that the insulating members47be arranged in the vicinity of the cell stacks2. It is particularly preferable that the insulating members47be arranged on the side surfaces of the cell stacks2extending in the direction in which the fuel cells32are arranged and that the insulating members47have a width greater than or equal to the width of the side surfaces of the cell stacks2in the direction in which the fuel cells32are arranged. It is preferable that the thermal insulating members47be arranged on both side surface sides of the cell stacks2. This makes it possible to effectively inhibit temperature decreases in the cell stacks2. Furthermore, this makes it possible to inhibit oxygen-containing gas led in by the oxygen-containing gas leading-in member35from being discharged from the side surface sides of the cell stacks2, thereby making it possible to promote the flow of oxygen-containing gas between the fuel cells32of the cell stacks2. Note that openings48are formed in the thermal insulating members47arranged on both side surface sides of the cell stacks2in order to regulate the flow of oxygen-containing gas to the fuel cells32and to decrease the differences in temperature in the lengthwise direction in which the fuel stacks2extend as well as in the direction in which the fuel cells32are stacked.

Moreover, on the inner sides of the inner walls41extending in the direction in which the fuel cells32are arranged, exhaust gas inner walls49are formed. The space between the inner walls41and the exhaust gas inner walls49forms exhaust gas flow paths50that allow the exhaust gas inside the power generation chamber43to flow from top to bottom. Furthermore, the exhaust gas flow paths50are communicated to an exhaust hole51formed at the bottom of the housing34. Further, the thermal insulating members47are provided on the cell stack2side of the exhaust gas inner walls49as well.

Accordingly, exhaust gases produced when the module1operates (during a startup process, power generation, or a shutdown process) flow through the exhaust gas discharge paths50and then are discharged through the exhaust hole51. Note that the exhaust hole51may be formed by cutting out a portion of the bottom of the housing34or by using a pipe-shaped member.

Note that, inside the oxygen-containing gas leading-in member35, a thermocouple52for measuring the temperature near the cell stacks2is formed such that a temperature sensing portion53of the thermocouple52is positioned at the center of the fuel cells32in the lengthwise direction and at the center in the direction in which the fuel cells32are arranged.

Further, in the module1configured as described above, at least a portion of the fuel gas and the oxygen-containing gas discharged from the fuel gas flow paths of the fuel cells32and not used in power generation is combusted between an upper end portion side of the fuel cells32and the reformers3, making it possible to increase and maintain the temperature of the fuel cells32. In addition, this makes it possible to heat the reformers3disposed above each of the fuel cells32(cell stacks2), and efficiently perform a reformation reaction in the reformers3. Furthermore, during normal power generation, the module1has a temperature of 500 to 800° C. due to the abovementioned combustion process and the generation of power in the fuel cells32. Therefore, the exhaust gas discharged from the module1also become extremely high in temperature.

FIGS. 5 and 6are configuration diagrams illustrating yet other examples of the configuration of the cooling and heating device of the present embodiment.FIG. 5illustrates the cooling function,FIG. 6illustrates the heating function, and the configuration of each device is the same. Thus, in the following descriptions of the configurations,FIG. 5will be mainly used for explanation.

The cooling and heating devices illustrated inFIGS. 5 and 6, compared to the cooling and heating devices illustrated inFIGS. 1 and 2, differ in that each use water as the first fluid, and include a hot water storage unit including a hot water storage tank54for storing hot water heated and produced by the heat exchanger6.

In the cooling and heating devices illustrated inFIG. 1andFIG. 2, there is still room for improving the effective utilization of the heat of the exhaust gas discharged from the module1, particularly when the cooling and heating switch has been turned off by user settings or automatic operation, and when the cooling and heating functions are in excess.

Here, in each of the cooling and heating devices illustrated inFIGS. 5 and 6, the hot water storage unit is provided, allowing hot water to be produced using the heat of the exhaust gas discharged from the module1and not used in cooling and heating. This hot water is thus provided as a hot water supply, making it possible to achieve a cooling and heating device having increased overall efficiency.

Here, the storage tank54includes water inflow piping56having one end connected to the first piping30via a third switching unit55and the other end connected to the hot water storage tank54, and water outflow piping58having one end connected to the storage tank54and the other end connected to the first piping30via a fourth switching unit57. Note that a pump59is provided between the heat exchanger6and the fourth switching unit in the first piping30, and the hot water storage tank54includes a stored water volume sensor and a stored water temperature sensor for measuring the temperature and volume of the hot water stored in the hot water storage tank54. These sensors are collectively referred to as hot water storage tank sensor60in the descriptions below.

For example, the following control is preferably performed to further improve overall efficiency in cases such as when the first fluid is not flowing through the circulation piping26, when the operation of the pump31satisfies a predetermined condition (operation shutdown continuing for at least one hour, for example) to activate the pump31so that the temperature measured by the temperature sensor29provided in the cooling/heating target area reaches a predetermined temperature range (a temperature of at least 10° C. and less than 25° C., for example), and when the temperature and the volume of the hot water measured by the hot water storage tank sensor60are less than or equal to predetermined ranges.

For example, the following describes the control performed on the basis of the temperature and the volume of the hot water measured by the hot water storage tank sensor60. First, the controller13determines if the temperature and volume of the hot water in the hot water storage tank transmitted by the hot water storage tank sensor60are within the predetermined ranges. When the temperature and volume are within the predetermined ranges, the controller13continues the control performed up to that time.

When the temperature and volume are outside the predetermined ranges, the controller13controls the exhaust gas switching unit25so that at least a portion of the exhaust gas discharged from the module1flows into the heat exchanger6. Then, the controller13controls the third switching unit55so that at least a portion of the hot water produced by the heat exchanger6flows to the water inflow piping56, and controls the fourth switching unit57so that the water in the hot water storage tank54flows into the heat exchanger6via the water outflow piping58.

Note that, when the control performed before this control requires the heating function, the controller13may control the third switching unit55and the fourth switching unit57so that a portion of the water that flows through the first piping30flows through the water inflow piping56and the water outflow piping58. On the other hand, when the control performed before this control requires the cooling function, the controller13may control the third switching unit55and the fourth switching unit57so that all of the water flows through the water inflow piping56and the water outflow piping58. The controller13, in addition to this control, controls the exhaust gas switching unit25so that all or a portion of the exhaust gas discharged from the module1flow into the heat exchanger6.

Specifically, when the temperature and the volume of the hot water in the hot water storage tank transmitted by the hot water storage tank sensor60are outside the predetermined ranges, and the temperature of outside air or the temperature of the cooling/heating target area satisfies the first condition (a temperature of at least 25° C. continuously for at least one hour, for example), the controller13may control the exhaust gas switching unit25so that the exhaust gas discharged from the module1is supplied into both the heat exchanger6and the thermoacoustic cooler14. Further, when the temperature of outside air or the temperature of the cooling/heating target area satisfies the second condition (a temperature of less than 10° C. continuously for at least one hour, for example), the controller13may control the exhaust gas switching unit25so that the exhaust gas discharged from the module1is supplied only to the heat exchanger6.

With such a configuration, the cooling and heating device further includes a hot water supply function in addition to the cooling and heating function, making it possible to achieve a cooling and heating device having increased overall efficiency.

Note that, in the above, when the first fluid is not flowing through the circulation piping26, and when the operation of the pump31satisfies a predetermined condition (operation shutdown continuing for at least one hour, for example) to activate the pump31so that the temperature measured by the temperature sensor29provided in the cooling/heating target area reaches a predetermined temperature range (a temperature of at least 10° C. and less than 25° C., for example) as well, the controller13performs control similar to that described above, making it possible to achieve a cooling and heating device control having increased overall efficiency.

The present invention has been described in detail above. However, the present invention is not limited to the embodiments described above, and various modifications or improvements can be made without departing from the spirit of the present invention.

For example, while the aforementioned hybrid system has been described using a fuel cell device that includes solid oxide fuel cells as an example of the fuel cell device, the fuel cell device may be a solid high polymer fuel cell device, for example. When a solid high polymer fuel cell device is used, the heat produced in the reformation reaction, for example, may be effectively utilized, and the configuration may be changed as appropriate.

REFERENCE SIGNS LIST