AT508315A2 - SOLAR SYSTEM - Google Patents

Description

solar system

Technical area

The invention relates to a solar system for the preparation of domestic hot water and or or for space heating, with a heat pump with evaporator and condenser for a refrigerant.

Thermal solar systems provide sufficient heat almost free of heat energy for the preparation of hot water and they support in many cases, the space heating. Heat pump systems extract energy from a heat source by cooling and raise this energy to a higher temperature level. The drive of the heat pump is usually done electrically. The lower the temperature increase, the more economical the heat pump works.

The invention aims to achieve a particularly good efficiency in the combination of a solar system with a heat pump. This is achieved in that the evaporator of the heat pump and a heat exchanger guided through solar panels heat cycle in a water-filled pressureless water / ice latent storage and the condenser of the heat pump and a heat exchanger for space heating in another latent memory, preferably filled with phase change material (English phase Chance Material = PCM) are installed. So it is a combination of a solar system with a heat pump and two latent storage provided, the first latent storage contains the evaporator and the other the capacitor. The latent storage with the evaporator cools down to the formation of ice and is referred to as water / ice latent storage. When a certain ice thickness is reached on the evaporator, a controller can cause a momentary reversal of the refrigerant circuit of the heat pump, and by supplying heat, the ice is released from the evaporator, whereupon it floats up in the water. So gradually a large part of the water in the container can be converted into ice and a large storage capacity can be used. The water / ice latent storage consists of a pressureless and water-filled container in which a heat exchanger package with individual rows of evaporator tubes of the refrigerant circuit of the heat pump and heat exchanger tubes for the supply of solar heat, but also waste heat from ventilation and waste water, are preferably provided near the ground , In this case, the evaporator tubes and the heat exchanger tubes are guided in pairs parallel to each other and connected in each case with fins for the direct transfer of solar heat to the refrigerant circuit, preferably soldered.

Advantages of the invention over the already known systems

Significant increase in solar heat yield:

The solar system also operates at a low temperature level, which increases the collector efficiency and even diffuse radiation of 100 W / m2 is already used. Collector temperatures from 7 ° C can be dissipated profitably.

With the direct charge of the PCM latent heat storage with solar heat, a large amount of energy is stored in the melting range of the PCM (about 3 K), the small temperature increase also improves the collector efficiency.

Significant improvement in the annual work rate of the heat pump:

By feeding the water / ice latent storage from the solar system, the heat pump is always a relatively high temperature level for heat extraction available, the evaporation temperature will hardly fall below 0 ° C (in contrast to grave collectors or deep wells).

The sensible heat of 17 kWh / m3 in the temperature range 20-0 ° C and the huge amount of energy of 93 kWh / m3 during the icing process are used.

The small temperature rise from 0 to 35 ° C - in the year cut about 5 to 35 ° C (at a low temperature heating), as well as the elimination of motive power for groundwater or brine pump and heating pump, or for the fan at air / water WP, is reflected in the energy balance is positive.

The waste heat of a controlled ventilation and waste water can be removed and recycled into the water / ice storage tank, the defrosting energy is not lost. The water tank of the water / ice latent tank can be placed in the basement (for example, in the former oil storage room) or buried in front of the house - using the surrounding geothermal energy.

The evaporator / heat exchanger can also be installed in rainwater cisterns, closed septic tanks or swimming pools.

Lock hours of the RUs are bridged by the PCM latent storage, so that the heat pump can be operated mainly with cheap night-time rates.

By buffering the PCM latent memory in the melting range of the PCM (about 3 K), the clocking in the partial load operation of the heat pump is avoided, thus increasing the service life.

Due to the high direct solar coverage and the favorable annual work rate of the heat pump, there is only a small demand for drive energy (electricity) for the heat pump, which ideally can be covered by a photovoltaic system. It is thus the realization of a self-sufficient heating possible.

Examples of practice of the invention presented to the drawings.

1 shows a block diagram of a solar system according to the invention, Figure 2 shows a cross section through a water / ice latent storage in a schematic representation, Figure 3 is a top view, Figure 4 is a detail of Figure 1 in section along the line IV - IV in Figure 2, Figure 5 a Side view of Figure 4 and Figure 6 is a section through a PCM latent memory.

FIG. 7 shows an evaporator / heat exchanger package with casing, FIG. 8 shows a side view of FIG. 7, FIG. 9 shows a water / ice latent storage with built-in tray.

According to Figure 1 solar panels 1 via circulation pump and valve 2 with a heat exchanger in a hot water tank 4 and a valve 5 and a heat exchanger 6 with a space heater 7 directly - but also connected to a heat exchanger 8 in a water / ice latent storage 9. The heat pump 10 has an evaporator 11 in the water / ice latent storage 9 and a capacitor 12 in a PCM latent memory 13, which also contains a heat exchanger 14 of the heating circuit for the space heater 7. If enough heat is absorbed by the collectors 1, then both the hot water tank 4 and the space heater 7 via the valves 2 or 5 can be fed directly. In addition, the heat from the collectors 1 can be released for storage in the PCM memory 13 latent and stored for a later date. If this is not sufficient, the heat pump 10 comes into action, it extracts heat from the evaporator 11 the water / ice latent storage by cooling heat until ice formation. The heat is released via the capacitor 12 to the PCM latent storage and fed via the heat exchanger 14 of the space heater (7).

Ice that forms on the tubes 4 and fins 24 on the evaporator 11 can be detached by briefly switching the refrigerant circuit, after which it floats up, where it is melted by supplying heat from the panels 1 through the heat exchanger 8 again. The defrost energy is not lost, it remains in the water / ice latent storage 9.

2 shows the water / ice latent storage in a schematic representation. A pipeline 20 comes from the heat pump 10 and leads to a register of evaporator tubes 21. Parallel run heat exchanger tubes 22 to a pipe 23 which are in the cycle of the solar panels 1. The evaporator and heat exchanger tubes 21 and 22 are connected by fins 24 and soldering 25. The entire unit - which shows a plan view in FIG. 3 - is provided in the lower region of the water / ice latent accumulator 9, which is designed as a pressureless, water-filled container.

FIG. 4 shows a detail of a small area from FIG. 2 from the side.

It should be noted that the pipes 21 and 22 need not necessarily be in a vertical plane, it may be advantageous to arrange them in a horizontal plane

6 shows the PCM latent memory 13 in section, it may correspond in its execution according to AT 504 794. In a pressureless container filled with phase change material (PCM, e.g., paraffin), two heat exchanger packages 30/31 are integrated, each consisting of an outer tube 14 'with mounted ribs 32 and an inner heat transfer tube 12'. The outer heat transfer tube 14 'is the vulnerable direct heat supply from the solar system 1 according to the heat exchanger 14 and the heat to the circuit of the space heater. The inner heat transfer tube 12 'serves as a condenser 12 of the heat pump 10 for heat supply. As is known, the phase change material (PCM, e.g., paraffin) provided in the pressureless vessel is made to melt by the supply of heat through the outer heat transfer tube 14 'and the inner heat transfer tube 12' and the drawn ribs 32, thus achieving the high storage capacity. I ί; · · ······ • κ · 2 1 * ····· ·

By removing heat via the outer Wärrhetfägörröbr * 14 'including the ribs 32 for the space heater 7, the molten PCM crystallized again, whereby the high storage capacity is used.

7 shows a variant of the water / ice latent accumulator, in which the evaporator (21) and heat exchanger tubes (22) with the lamellae (24) are installed in a flat-oval container-like casing (33) made of thin-walled CU sheet metal. The container is filled with glycol. When heat is removed through the heat pump through the evaporator tube, the glycol is cooled until ice forms on the surface of the container. After reaching a certain ice thickness, the glycol is heated by switching the refrigerant circuit of the heat pump and the ice is brought to melt. Due to the volumetric expansion of the glycol during heating, the container expands, causing the ice to detach from the surface and float upwards in the water container. A strip of poorly heat-conducting material avoids ice bridging between the two container walls.

In Fig 8, the evaporator (21) and heat exchanger tubes (22) with the slats (24) installed in a container-like casing (33) drawn from the side drawn.

Figure 9 shows the water / ice latent storage with an installation that allows a uniform cooling of the entire memory contents.

It consists of a trough (36) in which the water cooled by the evaporator flows downwardly and along the bottom to a centrally arranged opening (37) from the trough. By nachdrängende water it is laterally between the memory inner wall and the walls of the tub (38) back up. This avoids the formation of a cold water lake on the ground and there is a circulation of water with improved heat transfer.

The guidance of the cold water on the storage inner wall also facilitates the absorption of ambient heat and the buoyancy is supported.

Claims (8)

1. solar system for the preparation of domestic hot water in a hot water tank (4) and / or for space heating (7) with a heat pump (10) and evaporator (11) and condenser (12) for a refrigerant, characterized in that the evaporator (11) the heat pump (10) and a heat exchanger (6) of the solar collectors (1) guided heat cycle in a water-filled pressureless water / ice latent storage (9) and the condenser (12) of the heat pump (10) and a heat exchanger (14) for space heating in a further latent memory (13), preferably filled with phase change material (PCM) are installed 2. Solar system according to claim 1, characterized in that a control causes a momentary reversal of the refrigerant circuit of the heat pump (10) and by supplying heat, the ice from the evaporator (11) is released 3. Latent storage according to claim 1 or 2, characterized in that in a pressureless and water-filled container, a heat exchanger package with individual rows of evaporator tubes (21) of the refrigerant circuit of the heat pump and further from heat exchanger tubes (22) for the supply of solar heat preferably near the bottom are provided 4. Solar system according to claim 3, characterized in that the evaporator tubes (21) and the heat exchanger tubes (22) guided in pairs parallel to each other and connected respectively with fins (24) for the direct transfer of solar heat to the refrigerant circuit, preferably soldered (25) 5. latent storage according to claims 3 or 4, characterized in that the evaporator tubes (21) and the heat exchanger tubes (22) are provided in a horizontal plane of the water / ice latent storage (9) 6 latent storage according to one of claims 3 to 5, characterized in that each row of evaporator tubes (21) and heat exchanger tubes (22) with lamellas (24) are arranged in a container-like casing (33) which is filled with a liquid (eg glycol ), whose freezing point is below that of the surrounding water 7. A latent accumulator according to claim 4, characterized in that the sheathing (33) has a flat-oval cross-sectional shape and is preferably double-shelled with soldering edge (34), wherein a covering strip (35) of poorly heat-conductive material can be plugged over the soldering edge 8 latent storage according to one of claims 3 to 7, characterized in that in the container (9) is provided a rows of evaporator tubes and heat exchanger tubes with fins and possibly the shells receiving trough (36) in the bottom region a centrally disposed opening (37). for the outflow of cooling water flowing down and that at the edge there is a distance (38) between the tub and the container inner wall for the circulation upwards