FR2493487A1 - Outdoor heat pump system - has heat pump type heating and cooling unit with heat collecting and radiating panel disposed outdoors and indoor air-conditioning unit - Google Patents

Abstract

A heat pump type heating and cooling source system has a heat collecting and radiating panel connected in a primary medium circulating circuit arranged for heat exchange relation with a secondary medium circulating circuit including an indoor air-conditioning unit. The heat collecting and radiating panel is disposed outdoors to stand substantially normal to the horizontal and is oriented to extend from east to west. Surface treatment is applied to improve the rate of heat radiation.

Description

Heating and refrigeration system using a solar and atmospheric heat pump
The present invention relates to a heating and refrigeration system using a solar source and atmospheric heat pump. It relates more particularly to an outdoor element of such a system, as well as to improvements within this system.

 In a conventional heat pump heating system using solar radiation, a heat collecting panel is arranged with an inclination of 30 to 600 or following the inclination of a roof in order to increase the amount of energy solar collected on this panel.

 Such a conventional system, however, has an inevitable defect heat can not be collected in the absence of solar radiation which is the case on cloudy days or at night. Even if heat is raised on the ambient air, the amount withdrawn is very small. As a result, the value of the overall yield is considerably lowered.

 In order to avoid the drawback mentioned above, the object of the present invention is first of all to provide a new system which makes it possible to obtain the same efficiency by natural convection as a conventional air source heat pump system in the absence solar radiation and which also allows to obtain increased efficiency in the presence of solar radiation.

 The present invention therefore relates to a heating and refrigeration system using a heat pump solar source and atmospheric, this system being characterized in that it comprises - a circuit for the circulation of a primary coolant with use of the latent heat of this refrigerant fluid, - a circuit for the circulation of a secondary fluid disposed in heat exchange relation with said circuit for the circulation of the primary fluid and having an action member adapted to provide the desired heating or cooling and at least one heat-collecting element and heat radiation in the form of a panel and connected in said circuit for the circulation of the primary coolant medium, this heat collection and radiation element being disposed outside so that substantially normal to the horizontal and being adapted to absorb heat from the ground radiation and from the amosphere, and being also adapted to evacuate heat in the atmosphere, - said primary coolant circulating in said circulating system, when it is required to carry out heating in winter, in said element in the form of panel has an evaporation temperature which does not substantially exceed that of the surrounding air and ee element which allows this primary coolant to absorb the solar radiation and the atmospheric heat, this same circulating coolant circulating, when it acts to carry out cooling in summer, at a temperature of ondensation exceeding the air temperature surrounding this panel-shaped element, which allows this refrigerant to evacuate heat into the atmosphere through this element, said primary coolant was essentially the only fluid element used in the system to absorb heat from the outside and to evacuate it in this environment.

According to this invention a suitable thermal equilibrium is obtained between the solar heat and the heat from the atmosphere collected on the panel-shaped element by virtue of the substantially vertical arrangement of this element, which arrangement minimizes the amount of solar radiation. received by the panel
Even if the amount of solar radiation received is decreased there is no appreciable loss of heat due to radiation, nor a decrease in heat capture efficiency since the temperature of the heat collected is kept at or below the temperature. outside air thanks to the action of the heat pump.

 In the preferred embodiment, the primary coolant is designed to circulate, when winter heating requirements dictate, in the panel-shaped member at a vaporization temperature ranging from -20 C to + 20 C when the ambient cold air is at a temperature higher than -20 C. In this same embodiment, this fluid is designed to circulate in summer for the needs of refrigeration at a condensing temperature ranging from OOC to 600C when the ambient air exceeds approximately 35 ° C.

In addition, said heat collecting and radiating element is subjected to a surface treatment using a material which improves the rate of thermal radiation.

 The following is a brief description of the figures attached.

 Fig. 1 is a schematic diagram of the hydraulic circuit of a preferred embodiment of the present invention.

 Figure 2 is a schematic sectional view along line AA 'of Figure 1, intended to show the structure of a radiating panel and collecting heat.

 Figure 3 is a schematic side elevational view, showing a set of panels collecting and radiating heat, arranged substantially perpendicular to the horizontal.

 FIG. 4a is a front view in elevation of the panels of FIG.

 Figure 4b is a perspective view of a modified version of these panels.

 Figs. 5a and 5b are schematic diagrams showing the basic cycles of the system according to the present invention.

Figures 6a and 6b are Ph diagrams of this system:
P representing the pressure and h enthalpy. In these figures, the parts of the diagram representing the variations of these quantities in an element of the system are designated by the same reference number as this element.

 Figure 7 is a view similar to Figure 1 but showing a modification of the system according to the present invention.

 Fig. 8 is a hydraulic circuit diagram showing a heat absorbing cycle according to another modification of the system according to the present invention.

 Fig. 9 is a hydraulic circuit diagram showing the heat radiation cycle in the variant shown in Fig. 8.

 Fig. 10 is a hydraulic circuit diagram showing the heat absorbing cycle in another variation of the system according to the present invention.

 Preferred embodiments of the present invention will now be described.

 The diagram of FIG. 1 shows an application of a preferred embodiment of the solar and atmospheric heat pump heating and cooling system according to the present invention, this system being applied to the air conditioning device of a House. In Figure 1, the solid arrows indicate the heating cycle of the heat pump and the broken arrows indicate the refrigeration cycle of the heat pump.

 In Figure 1 the system comprises at least a panel 1 radiating and collecting heat. This panel is disposed at the top of the house or on the roof, in a plane substantially normal to the horizontal as shown in Figure 3. The panel 1 radiating and collecting the heat is of the type "sheet and tube" which can be manufactured with good productivity. The roll-bond rolled bond method on aluminum foils is especially suitable for the mass production of such panels at low cost. The radiating and heat-collecting panel 1 comprises tube segments 1 'ensuring the circulation of the refrigerant and a segment of fin 1 "as seen in FIG. 2. A refrigerant such as the fluorocarbon sold under the brand Freon R22 crosses a compressor 6 and traverses the ducts being properly oriented by a four-way valve 5 so as to perform either the heat-absorbing cycle in which the temperature of the panel 1 is lower than the temperature of the outside air which allows the panel to absorb heat from the ambient air, the heat radiation cycle in which the temperature of panel 1 is greater than the outside air temperature, which allows it to give up heat As in a conventional device, the system of the present invention comprises control valves 2, 4, 13 and 14, an expansion valve 3 and a refrigerant receiver 7.This circuit The purpose of fluorocarbon is to allow heat exchange at a heat exchanger 8 supplied with water. The hot or cold water obtained as a result of the heat exchange in the exchanger 8 is entrained in a storage tank 11, via a pump 12, to be stored therein.

It is taken up in this tank at the desired time by means of another pump 10 for supplying an inner element, for example a radiator 9 placed in a room.

 When, in the case of the heat-absorption cycle, the vaporization temperature of the fluorocarbon is set between -200 ° C and + 200 ° C, given that of the ambient air on a winter day, this theoretically allows the collection of heat by sampling on ambient air above -20 C, and therefore also allows storage and hot water at about 450C in the storage tank 11.By cons, in the case of heat radiation cycle in summer, cold water can be stored in sufficient quantity even if the ambient air temperature is about 350C, since the condensing temperature of refrigerant circulating in the panel 1 collecting and radiating heat is set between about 40 C and 600C and since the ambient air temperature during the night is lower than this. The temperature of the cold water thus stored can be maintained between 50C and 80C, for example, which is sufficient for refrigeration purposes.

 In general, in the case of the heat absorption cycle, the temperature of the coolant does not significantly exceed the temperature of the air surrounding the panel, this to allow the absorption of solar and atmospheric heat.

 In the case of the heat radiation cycle, the temperature of the refrigerant exceeds the temperature of the air which ensures the heat transfer by contact of the panel with the surrounding air and by low temperature radiation.

 Particularly effective operation of the system by radiating heat to the outside can be achieved mainly during the night which allows storage of cold water and its use for refrigeration needs during the day.

The impossibility of refrigerating in summer can be avoided since heat can be radiated outward even during the day when the temperature of the water stored in the storage tank 11 rises.

 Figure 3 shows a set of radiating and heat collecting panels 1 arranged parallel to each other at the top of the house or on its roof in planes perpendicular to the horizontal. Figure 4a is a front view of one of these panels 1. Figure 4b shows a variant of these panels.

 A coolant distributor 15 and a heater 16 are connected to these panels 1. The surface of these radiant and heat collecting panels is treated with a war. Such a coating, such as black or white paint, improves the efficiency of heat radiation. As described above, this improvement in the efficiency of heat radiation is the result of the ease of absorption of the heat. solar radiation and heat from the heat sources to the self during the heat-absorbing cycle and from the best infrared radiation from the panels 1 themselves radiation radiating heat during the cycle of For example, a black coating or the like is suitable for both absorption and heat radiation since it has a high rate of heat absorption (= radiation rate of heat) of the order of a, g to both in the visible and infrared spectral ranges, whereas the white coating or the like is only suitable for heat radiation since it has a low rate of heat absorption (radiation) of the order of 0.1) 0.2 in the visible range and a high rate of heat absorption (radiation) of the order of 0.9 equivalent to that of the black coating in the infrared spectrum range. the surface of the heat-collecting and radiating panels 1 may have a black coating on the solar-receiving tee and a white coating on the opposite side.

Instead of applying a coating material, the radiating and heat collecting panels 1 can be chemically stained. Such a surface treatment is particularly necessary for the shiny surface of a metal, for example aluminum, which has a low rate of absorption of heat and radiation of the order of 0.1 at a time in the spectral domains. visible and infrared which consequently leads to a reduction in the heat exchange capacity by radiation.

 Provided that the heat dissipation operation is reserved for night hours, both sides of the panel will be painted black, which will absorb the solar energy on both sides, especially when this energy comes uniformly from all the regions of the sky.

The angle of 900 that the panel makes with the horizontal is established taking into account the following (1) solar heat absorption in winter (2) sufficient heat exchange capacity with outside air, (3) proper solar participation that can be taken up by
an air source without extreme measures (4) minimization of snow accumulation to avoid any insulation
thermal (5) minimization of dust accumulation to prevent
corrosion of the panel and avoid periodic cleaning of the panel,
and, (6) minimizing panel heating by summer insolation
if the dissipation of heat is necessary in the day.

 The vertical configuration meets almost all the requirements mentioned above.

 The object of the invention is to use solar energy under the best conditions while ensuring sufficient capacity of the air source. As a result, in the case of exclusive operation on the air source, the vaporization temperature of the refrigerant should not be lower than that of conventional air source heat pumps which have the same external temperature to maintain the power. heating in cloudy weather.

In the case of complete solar operation, the panel temperature should not be greater than that of the ambient air to prevent heat loss, while increasing the thermodynamic efficiency in sunny weather.

In relation to the above, one can write as follows the ratio between the heat qa absorbed per unit area of panel in the case of exclusive operation on air source and the heat qs absorbed in the case of exclusively solar operation q5 qs = 2 <t (ta - tp): a (Ip1 + Ip2) ... (1) where 9 (t = overall heat transfer coefficient (Wm 2K 1);
t: outside air temperature (OC)
t = average panel temperature (OC); p
a = radiation absorption coefficient, 0.9;
Ip1 2 = insolation on faces 1 and 2 (Wm 2);
Equation (1) can be rewritten 1p1 + Ip2 = 2 a (tat) (s) ... (2)
When the outdoor temperature t is 70C, the temperature of the panel tp should be 0 C for t = 23 iWm 2K 1 in case of exclusive operation on air source, to have a power comparable to that of conventional heat pumps with air source. In the case of exclusive solar operation, the panel and coolant vaporization temperatures should rise from 7 K to the same tt and then q3 should rise to approximately 1.3 times qa. Applying these values to equation (2), 1p1 + Ip2 becomes equal to about 465 Wm-2.

Such solar radiation intensity is typical of a vertical plane facing south and north. In the region of
In Tokyo, this intensity exceeds 700 Wm2 at noon during the sunny days around the winter solstice and therefore becomes greater than t, which must lead to some loss of heat. In practice, this loss can be neglected.

Since the heat pump system has a tendency, when the outside temperature in sunny daytime period, to increase its heat absorption capacity as well, this tendency will be manifested advantageously by decreasing the heat loss.

 Any azimuth can be chosen for this collector and night radiator. But the vertical plane facing the south absorbs during the day a maximum of solar energy during the coldest period of the year.

 When the radiating and heat-collecting panels 1 described above are used in intermediate latitude regions the energy of the solar radiation can be sufficiently absorbed during the day to provide heating in winter and the heat can be diffused during the night by radiation of the panels to the outside which ensures refrigeration in summer. The diffusion of heat radially outward is sufficient even during the day in summer in such areas since the panels will not be excessively heated. In the case of low latitude regions, it is the cooling that is essential and the system works exclusively to radiate heat to the outside.This heat radiation is mainly during the night and cold water is stored in a storage tank 11 used for refrigeration.

 The radiation of heat directed outwards during the day is possible even when the amount of cold stored is insufficient, since the altitude of the sun is high in these regions of low latitude and the solar radiation passes between the panels 1 radiating and collecting heat almost parallel to them without heating them much. In the case of high latitude areas, heating is mainly required and the system operates exclusively for heat absorption. In these regions the solar radiation can fall on the radiating panels 1 and collecting the heat at an angle close to the right angle. However, these panels 1 should not be excessively heated since in these regions, the outside air temperature is generally low and the solar radiation is also low.

 To facilitate the understanding of this invention, the fundamental cycles are shown in FIGS. 5a to 6b. In the heating cycle, the low pressure liquid refrigerant vaporizes in the panel passages, absorbing solar energy and / or enthalpy of the air as latent heat of vaporization.

 The gaseous refrigerant is then sucked by a compressor 6, in which the pressure and the temperature rise. The hot gas 21 released at the outlet of the compressor 6 goes to the heat exchanger 8, the water of which is the refrigerant and where it condenses at 22. It then provides its enthalpy of liquefaction with hot water 23 flowing towards the radiators 9 parts. The high-pressure liquid refrigerant 24 then passes through an orifice called expansion valve 3 and its pressure and temperature are lowered with spouting of liquid particles. This cold liquid at low pressure (with gas) returns to panel 1 and the cycle starts again.

 In the refrigeration cycle X valves change the direction of fluid flow. The panel 1 becomes a condenser and the water heat exchanger 8 functions as an evaporator to cool the water. The condensation takes place at 39 and the evaporation at 31, the cooled and partially peeled water being reprosented at 32. In FIGS. 6a and 6b, the compression work is represented at 40.

 A variant of the system of the present invention is shown in FIG. 7. In this variant, 1 refrigerant supplied by the circuit of the heat pump flows to the radiating panel 1 and collects the heat after heat exchange in the heat exchangers. heat 17 instead of going directly to the radiating and heat collecting panel 1 More specifically, the circuit of the heat pump is connected to the c-o-heating tubes 1 'through the heat exchanger 17 In this case too , heat is transferred by the refrigerant into the heating tubes 1 'thanks to the latent heat of the refrigerant.

 Figures 8 and 9 show another variation of the system of the present invention. In this variant, a liquid refrigerant such as fluorocarbon cited above is driven by a pump 122 for the circulation of the refrigerant. In Fig. 8 showing the heat absorption cycle, the refrigerant in the form of liquid is pumped out of the storage tank 11 by the pump 12 'in order to supply the radiating panel and collecting the heat 1 and most of the The refrigerant is converted to gas while the remaining unprocessed portion does not affect operation.

The refrigerant in the form of gas enters the heat exchanger 8 of the heat pump circuit to be reliqued thereby providing heat to the heat pump.

 FIG. 9 shows the heat radiation cycle in which the refrigerant circulation is reversed with respect to that illustrated in FIG. 8. In these figures, the refrigerant circuit of the heat pump is represented at 50.

 Figure 10 shows another variant of the system according to the present invention. In this variant also a pump 12 'is intended for the circulation of the refrigerant and it is also designed to drive the fluorocarb-one to a group of panels 1. It has been confirmed experimentally that the de-icing operation is not necessary when the exchange surface of the panels with the air is large and when the distance between the panels is large.

 With respect to the preferred embodiments of the present invention described in detail in the previous section, it is obvious that the present invention is not limited in any way to such embodiments and that changes and modifications various may be made without departing from the spirit of the present invention. For example, the present invention applies not only to the air conditioning referred to above, but also to the heating of water in a heated pool, the melting of snow, the storage of food in a cold warehouse, etc.

Claims (5)

1 / Heating and cooling system using a solar source heat pump and atmospheric, characterized in that it comprises - a circuit (1, 2, 3, 4, 5, 6, 7, 8, 13 , 14) for the circulation of a primary coolant with use of the latent heat of this coolant, - a circuit (8, 9, 10, 11, 12) for the circulation of a secondary fluid arranged in relation to heat exchange with said circuit for the circulation of the primary fluid and comprising an action member adapted to provide the desired heating or cooling, and at least one heat-collecting element and heat radiation having the shape of a panel (1 ) and connected in said circuit (1, 2, 3, 4, 5, 6, 7, 8, 13, 14) for the circulation of the primary coolant medium, this heat collection and radiation element being disposed outside substantially normal to the horizontal and being adapted to absorbing heat from the solar radiation and from the atmosphere, and being also adapted to evacuate heat in the atmosphere, - said primary coolant circulating in said circulating system, when it comes to heating in winter, in said panel-shaped element (1) to an evaporation temperature which does not substantially exceed that of the air surrounding this element, which allows this primary coolant to absorb the radiation solar energy and the atmospheric heat, this same primary coolant flowing, when it is a question of cooling in summer, at a temperature of condensation exceeding the temperature of the air surrounding this panel-shaped element (1), this which allows this cooling fluid to evacuate heat into the atmosphere through this element, said primary refrigerant essentially constituting the only fluid element used in the system to absorb heat from the outside environment and to evacuate it in this medium. 2 / heating and refrigeration system using a solar source heat pump and atmospheric according to claim 1, characterized in that said collection element and heat radiation (1) is subjected to a surface treatment at the using a material that improves the rate of heat radiation. 3 / Heating and refrigeration system using a solar source and atmospheric heat pump according to claim 1, characterized in that the primary coolant is chosen, when it comes to heating in winter, to circulating in the panel-shaped element (1) at a vaporization temperature of between -200 ° C and about 200 ° C when the ambient cold air is below -200 ° C, and that the fluid is selected when it is a question of ensuring a cooling in summer, so as to circulate at a condensation temperature of between 400C and 600C when the temperature of the air is above 350C approximately. 4 / heating and refrigeration system using a solar source heat pump and atmospheric according to claim 1, characterized in that said primary coolant is essentially the only fluid element used in the system to absorb heat from the outside environment and to evacuate it in this environment. 5 / Heating and refrigeration system using a solar source and atmospheric heat pump according to claim 1, characterized in that when it comes to providing heating, the refrigerant circuit in the system is as follows the refrigerant is extracted from a refrigerant supply (7), it then passes through an expansion valve (3) suitable for allowing the refrigerant to expand, it then passes into said panel-shaped element (1) so as to absorb the solar radiant heat and the atmospheric heat, then in a compressor (6) to be compressed, it passes again in a heat exchanger (8) to cool there by heating a heat exchange fluid, and it returns finally to said reserve (7), and in that in the case of cooling, the refrigerant circuit in the system is as follows: the refrigerant is removed from a refrigerant supply (7) , he crosses then the expansion valve (3), then the heat exchanger (8) for heating therein by cooling a heat exchange fluid, it then passes into a compressor (6), then in said panel-shaped element (1) to give up its heat, and it finally returns to the refrigerant supply (7).