Air conditioning system

Abstract

To improve energy efficiency while preventing dew condensation and frost formation on a coil surface of an outdoor unit in winter by performing optimum exhaust utilization according to weather conditions.SOLUTION: In winter or during heating when the outside air temperature is low, the switching damper 260 is switched so that the inner casing 210 side is "closed" and the heat exchange gap 230 side is "opened", and the indoor exhaust air is supplied to the heat exchange gap 230 side. Thus, the heat of the indoor exhaust air warms the inside of the inner casing 210 by the sensible heat exchanger 212, and further warms the refrigerant coil 110. The indoor exhaust air introduced into the heat exchange gap 230 is exhausted from the opening 232 after heat exchange by the sensible heat exchanger 212.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air conditioning system, and to an improvement in an air conditioning system that utilizes exhaust heat from the room to be air-conditioned to improve operational efficiency and save energy. [Background technology]

[0002] For example, in Tokyo, indoor exhaust air is generally lower in temperature and humidity than outdoor air in the summer, and higher in winter. Therefore, it is believed that utilizing indoor exhaust air that is otherwise released into the atmosphere could reduce the energy consumption required for indoor air conditioning. One example of background technology utilizing indoor exhaust heat is the "method for efficiently operating a heat pump air conditioner or heat source unit using air conditioning exhaust air from occupied rooms in a building," described in Patent Document 1 below. This method switches between exhaust air and outdoor air, using exhaust air at a temperature lower than the outdoor air temperature during cooling and exhaust air at a temperature higher than the outdoor air temperature during heating, thereby increasing the operating efficiency of air conditioning in occupied rooms in a building and reducing the energy consumption required for air conditioning. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-102987 Summary of the Invention [Problem to be solved by the invention]

[0004] In summer, the temperature and humidity of exhaust air from indoors is lower than the outdoor temperature and humidity, and the refrigerant temperature of the outdoor unit of a heat pump system is high, so by directing the exhaust air to the outdoor unit, the energy consumption of the heat pump system can be reduced. However, in winter, if indoor exhaust air with a high moisture content is directed at the outdoor unit of a heat pump system, condensation and frost will form on the surface of the refrigerant coil of the outdoor unit when the temperature is below freezing, which can cause problems such as reduced heat exchange efficiency.

[0005] This is shown in Figure 3, where (A) shows a heat pump outdoor unit 100 of a heat pump system such as an air conditioner, water heater, or heat source machine. The refrigerant coil 110 of the heat pump outdoor unit 100 is housed in a casing 120. Outside air is introduced into the casing 120 through an inlet 130, and heat inside the casing 120 is exhausted through a heat exhaust fan 140. Meanwhile, exhaust air from the room to be air-conditioned is introduced into the casing 120 through an exhaust duct 150, and a switching damper 160 switches between introducing and not introducing the indoor exhaust air into the casing 120.

[0006] In summer, frost does not form on the refrigerant coil 110, so the switching damper 160 is switched as shown in FIG. 1(A) so that the indoor exhaust air always hits the refrigerant coil 110. On the other hand, when the indoor exhaust air is stopped, or when air conditioning is performed during the spring and autumn months, or in winter, it may be more efficient to use outside air. Also, in winter, the surface temperature of the refrigerant coil 110 drops, so if the humid indoor exhaust air is directly hit on the refrigerant coil 110, condensation and frost will occur. Therefore, the switching damper 160 is switched as shown in FIG. 1(B) to prevent the indoor exhaust air from hitting the refrigerant coil 110.

[0007] That is, in summer, the temperature and humidity of the exhaust air is lower than the outdoor air temperature and humidity, while the refrigerant temperature of the heat pump outdoor unit 100 is high, allowing for effective use of the exhaust air. However, in winter, the moisture content of the exhaust air from indoors is high, and when the indoor exhaust air is blown into the heat pump outdoor unit 100, the coil surface temperature of the outdoor unit 100 is below freezing, causing frost to form on the coil surface and reducing operating efficiency. As such, with conventional methods, the indoor exhaust air is directly exhausted to the outside, particularly in winter, wasting the energy contained in the indoor exhaust air and resulting in poor operating efficiency.

[0008] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to improve energy efficiency while preventing condensation and frost on the surface of the outdoor unit's coil in winter by making optimal use of exhaust air in accordance with weather conditions. [Means for solving the problem]

[0009] The present invention provides a. In the summer, the exhaust heat from the room is blown directly to the outdoor unit, and when air conditioning is performed in the intermediate seasons or winter when the outside temperature is lower than the exhaust temperature, the blowing direction is switched so that outside air can be actively utilized. b) In winter, in order to utilize indoor exhaust air in a heat pump system, it is necessary to remove the latent heat generated by indoor humidification and the sweating and breathing of residents. Therefore, we provide a system that can utilize only the sensible heat of indoor exhaust air through a sensible heat exchanger. One aspect of the present invention is an air conditioning system having a heat pump outdoor unit, wherein a casing housing a refrigerant coil of the heat pump outdoor unit has a two-layer structure consisting of an inner casing and an outer casing, a sensible heat exchanger is provided in the inner casing, and a switching means is provided for supplying exhaust air from the room being air-conditioned to the refrigerant coil together with outside air during cooling and between the inner casing and the outer casing during heating. According to one main aspect, the switching means is a switching damper provided in a duct that supplies the indoor exhaust air to the refrigerant coil.

[0010] Another invention is an air conditioning system having a heat pump outdoor unit, characterized in that the refrigerant coil of the heat pump outdoor unit is housed in a casing, and the system is equipped with a sensible heat exchanger that performs sensible heat exchange between the indoor exhaust air and outdoor air, and a switching means that supplies the indoor exhaust air to the casing during cooling, and supplies outdoor air that has undergone sensible heat exchange with the indoor exhaust air in the sensible heat exchanger to the casing during heating.

[0011] According to one main aspect, the air conditioner includes a first open / close damper provided at an inlet for taking in outside air into the casing, a second open / close damper provided at a duct for taking in room exhaust air into the casing, and a third open / close damper provided at the room exhaust air inlet side of the sensible heat exchanger, and the switching means closes the first and third open / close dampers and opens the second open / close damper during cooling, and closes the first and second open / close dampers and opens the third open / close damper during heating. According to another aspect, the air conditioner includes a fan that operates during cooling, provided at the discharge side of the sensible heat exchanger to the casing. The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. [Effects of the Invention]

[0012] According to the present invention, particularly during heating, the heat of the indoor exhaust air is supplied to the refrigerant coil using a sensible heat exchanger. This prevents a decrease in heat exchange efficiency on the surface of the refrigerant coil due to frost formation caused by humid indoor exhaust air directly hitting the refrigerant coil, and prevents energy loss caused by the outdoor unit performing defrosting operation, while making effective use of the heat from the indoor exhaust air, thereby improving energy efficiency. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are diagrams showing the configuration of the main parts of an air conditioning system according to a first embodiment of the present invention, where (A) shows the state during cooling and (B) shows the state during heating. [Figure 2] 10A and 10B are diagrams illustrating the configuration of the main parts of an air conditioning system according to a second embodiment of the present invention, in which (A) shows the state during cooling, (B) shows the state during cooling when the outside air temperature is low, and (C) shows the state during heating. [Figure 3] 1A and 1B are diagrams showing the configuration of the main parts of an air conditioning system according to the related art, where (A) shows the system in cooling mode and (B) shows the system in heating mode. DETAILED DESCRIPTION OF THE INVENTION

[0014] The best mode for carrying out the present invention will be described in detail below with reference to examples. [Example]

[0015] First, a first embodiment of the present invention will be described with reference to FIG. 1. Components corresponding to those in the background art described above will be designated by the same reference numerals. FIG. 1 shows the configuration of this embodiment. A heat pump outdoor unit 200 for a heat pump system, such as an air conditioner, water heater, or heat source, has a two-layer structure including an inner casing 210 and an outer casing 220. The inner casing 210 houses the refrigerant coil 110 described above. An inlet 130 is provided in the inner casing 210 for introducing outside air, and the air or heat inside the inner casing 210 is exhausted through a heat exhaust fan 140. A heat exchange gap 230 is formed between the inner casing 210 and the outer casing 220, and air is exhausted to the outside through an opening 232 on the heat exhaust fan 140 side. The purpose of introducing outside air is to balance the exhaust and intake air volumes of the heat exhaust fan 140. Since the indoor exhaust air has a higher pressure than the outside air, if there is sufficient indoor exhaust air, the outside air will not be introduced into the refrigerant coil 110.

[0016] On the other hand, exhaust air from the room to be air-conditioned is introduced into the inner casing 210 or the heat exchange gap 230 through the exhaust duct 150, and a switching damper 260 is capable of switching between supplying the indoor exhaust air to the casing 120 and supplying the indoor exhaust air to the heat exchange gap 230. Furthermore, in this embodiment, a sensible heat exchanger 212 is provided in the inner casing 210. This allows only sensible heat to be exchanged between the inner casing 210 and the heat exchange gap 230.

[0017] Next, the operation of this embodiment will be described. In summer when the outside air temperature is high or during cooling, as shown in Figure 1(A), the switching damper 260 is switched so that the inner casing 210 side is "open" and the heat exchange gap 230 side is "closed," and indoor exhaust air is supplied to the inner casing 210 side together with outdoor air. In summer or during cooling, even if the indoor exhaust air hits the refrigerant coil 110, there is no risk of condensation or frost formation because the surface temperature of the refrigerant coil 110 is high, and the refrigerant coil 110 is cooled well by the indoor exhaust air, which is lower in temperature than the outdoor air.

[0018] On the other hand, in winter when the outdoor temperature is low or during heating, as shown in FIG. 1(B), the switching damper 260 is switched so that the inner casing 210 side is "closed" and the heat exchange gap 230 side is "open," and the indoor exhaust air is supplied to the heat exchange gap 230 side. As a result, the heat contained in the indoor exhaust air is used by the sensible heat exchanger 212 to warm the inside of the inner casing 210 and further warm the refrigerant coil 110. The indoor exhaust air introduced into the heat exchange gap 230 is subjected to heat exchange by the sensible heat exchanger 212 and then exhausted from the opening 232. Similarly, during cooling in the intermediate seasons or when the outdoor air temperature is lower than the indoor exhaust air temperature, the outdoor air is preferentially introduced into the refrigerant coil 110, thereby making effective use of the outdoor air.

[0019] As described above, according to this embodiment, a) Condensation and frost formation caused by indoor exhaust air directly hitting the refrigerant coil 110 can be prevented, while the heat of the indoor exhaust air can be effectively utilized, thereby improving energy efficiency. b. In winter, the temperature of exhaust air from indoors is over 20°C, and even after passing through a total heat exchanger, it is only about 10°C, while the outdoor air temperature is even lower. Therefore, energy savings can be expected by utilizing the exhaust heat. In addition, in winter, peak heating loads occur during the morning and evening air conditioning hours when temperatures are low. Therefore, the benefit of reducing electricity consumption by consumers during these times is also significant in terms of improving the reserve margin of power companies. Furthermore, because the heat recovered by the sensible heat exchanger 212 is regenerated via the heat pump system, even when low-purity warm exhaust air such as factory exhaust is used as the indoor exhaust air, the risk of health damage due to the leakage of gases harmful to the human body can be avoided, so the heat from the factory exhaust can be used to heat an office, for example. Similarly, exhaust heat from unclean places such as toilets, which is lower or higher in temperature than the outside air, can also be used. [Example]

[0020] Next, a second embodiment of the present invention will be described with reference to Figure 2. Figure 2 (A) shows cooling in summer, (B) shows cooling when the outdoor air temperature is low, and (C) shows heating. In the previous embodiment, the casing of the heat pump outdoor unit 200 had a double structure and a sensible heat exchanger was provided in the gap between them, but in the heat pump outdoor unit 300 of this embodiment, the sensible heat exchanger is provided on the indoor exhaust duct side.

[0021] In FIG. 2, an opening / closing damper 330 is provided at an inlet 130 through which outside air is introduced into the casing 120, and opening and closing this damper allows the introduction and blocking of outside air into the casing 120.

[0022] Exhaust duct 150 for indoor exhaust is connected to direct duct 350 and heat exchange duct 360, and outside air duct 370 is provided in parallel to heat exchange duct 360. Direct duct 350 is provided with open / close damper 352, and heat exchange duct 360 is provided with open / close damper 362, sensible heat exchanger 372, and air supply fan 364, in that order. Sensible heat exchanger 372 is provided between heat exchange duct 360 and outside air duct 370, and sensible heat exchange occurs between the indoor exhaust air and the outside air.

[0023] Next, the operation of this embodiment will be described. During cooling in the summer, as shown in FIG. 1(A), the indoor exhaust air, which is at a lower temperature than the outside air, is used to the maximum extent possible. That is, a) The open / close damper 330 of the outside air inlet 130 of the casing 120 is set to "closed." b) The open / close damper 352 of the direct duct 350 is set to "open." c) The open / close damper 362 of the heat exchange duct 360 is closed, and the air supply fan 364 is stopped. Therefore, the indoor exhaust air passes through the direct duct 350 as it is and is supplied into the casing 120, where it directly hits the refrigerant coil 110.

[0024] Next, when cooling when the outside temperature is low, only the outside air is used as shown in the figure (B). a) The open / close damper 330 of the outside air inlet 130 of the casing 120 is set to "open." b) The open / close damper 352 of the direct duct 350 is set to "closed." c) The open / close damper 362 of the heat exchange duct 360 is opened, but the air supply fan 364 is stopped. As a result, outside air is supplied into the casing 120 and directly hits the refrigerant coil 110. Because the outside air temperature is low, a sufficient cooling effect can be obtained using only the outside air. The operations of the open / close dampers 330, 352, 362 and the air supply fan 364 may be controlled collectively by a switching device 302 configured by a computer or the like or an air conditioning control device of the air conditioning system.

[0025] Next, when heating, the sensible heat of the indoor exhaust is utilized to the maximum extent possible, as shown in the same figure (C). a) The open / close damper 330 of the outside air inlet 130 of the casing 120 is set to "closed." b) The open / close damper 352 of the direct duct 350 is set to "closed." c) The open / close damper 362 of the heat exchange duct 360 is opened, and the air supply fan 364 is operated. As a result, the pressure loss in sensible heat exchanger 372 is compensated for by air supply fan 364, ensuring the necessary air volume to be supplied to refrigerant coil 110. The indoor exhaust air exchanges heat with outside air in sensible heat exchanger 372 and is then exhausted to the outside. Meanwhile, outside air warmed by sensible heat exchanger 372 is supplied into casing 120 and hits refrigerant coil 110. However, because only heat is exchanged in sensible heat exchanger 372, condensation and frost on refrigerant coil 110 are effectively prevented. If outside air can be introduced using only exhaust heat fan 140, air supply fan 364 may be replaced with a damper.

[0026] Other Embodiments The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention. For example, the following modifications are also included. (1) The heat pump outdoor unit shown in the above embodiment includes various types of units such as air conditioners, water heaters, and heat source units. (2) In the above embodiment, the present invention is applied to heating and cooling in the summer and winter in Tokyo, but may be applied as appropriate depending on the region and season. [Industrial Applicability]

[0027] According to the present invention, the heat of the indoor exhaust air is supplied to the refrigerant coil using a sensible heat exchanger, particularly during heating. This prevents condensation and frost from forming when the indoor exhaust air directly hits the refrigerant coil, while effectively utilizing the heat of the indoor exhaust air, thereby improving energy efficiency and making the system suitable for various air conditioning systems. [Explanation of symbols]

[0028] 100: Heat pump outdoor unit 110: Refrigerant coil 120: Casing 130: Entrance 140: Exhaust heat fan 150: Exhaust duct 160: Switching damper 200: Heat pump outdoor unit 210: Inner casing 212: Sensible heat exchanger 220: Outer casing 230: Heat exchange gap 232:Aperture 260: Switching damper 300: Heat pump outdoor unit 302: Switching device 330: Open / close damper 350: Direct duct 352: Open / close damper 360: Heat exchange duct 362: Open / close damper 364: Ventilation fan 370: Fresh air duct 372: Sensible heat exchanger

Claims

1. An air conditioning system having a heat pump outdoor unit, The casing for accommodating the refrigerant coil of the heat pump outdoor unit has a two-layer structure consisting of an inner casing and an outer casing, a sensible heat exchanger is provided in the inner casing; An air conditioning system characterized by having a switching means for supplying exhaust air from a room where air conditioning is being performed to the refrigerant coil together with outside air during cooling, and for supplying it between the inner casing and the outer casing during heating.

2. 2. The air conditioning system according to claim 1, wherein the switching means is a switching damper provided in a duct that supplies the indoor exhaust air to the refrigerant coil.

3. An air conditioning system having a heat pump outdoor unit, The refrigerant coil of the heat pump outdoor unit is housed in a casing. a sensible heat exchanger that exchanges sensible heat between the indoor exhaust air and outside air; a switching means for supplying the indoor exhaust air to the casing during cooling, and for supplying the outside air that has undergone sensible heat exchange with the indoor exhaust air in the sensible heat exchanger to the casing during heating; An air conditioning system comprising:

4. a first open / close damper provided at an inlet through which outside air is introduced into the casing; a second open / close damper provided in a duct that takes in indoor exhaust air into the casing; a third open / close damper provided on the indoor exhaust gas introduction side of the sensible heat exchanger, 4. The air conditioning system according to claim 3, wherein the switching means closes the first and third on-off dampers and opens the second on-off damper during cooling, and closes the first and second on-off dampers and opens the third on-off damper during heating.

5. 4. The air conditioning system according to claim 3, wherein a fan that operates during cooling is provided on the discharge side of said sensible heat exchanger to said casing.

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