DE3109443A1 - Cooled PCM device for space heating and cooling by means of direct solar energy or indirect solar energy bound by water - Google Patents

Abstract

According to the invention, in order to avoid heat losses use is made outside the heated space only of heat sources (heat stores) which are colder than the environment. Consequently, it is chiefly the heat dissipated during the phase change which is utilized, and the temperature is brought to a higher level by means of a heat pump. The evaporation of the primary working medium is performed directly in the heat sources, for example: heat from the icing of liquids, heat from boiling black liquid of the solar collectors, waste heat from the heating system itself, waste heat from the use of hot water, waste heat from air ventilation. The primary working medium is compressed in a common heat pump assembly. The costs of procuring and repairing the compressors are reduced by mechanical simplifications and a substantially lowered working pressure. The difference between the condensation temperature and evaporation temperature is reduced by means of larger evaporators and condensers. The compression work thus diminished is distributed over a plurality of small, identical, i.e. cost-effective compressors. The two or more working media are cooled before expansion at least down to the evaporation temperature, in order to prevent the harmful formation of gas. This waste heat is utilized in common with waste heat from all the devices.

Description

P.Klami

Cooled latent heat storage for space heating and cooling by means of direct or water-bound, non-direct

Solar energy .

The invention relates to the memory of the direct or from the water bound solar radiation heat from which thermal energy is extracted by means of heat pumps and the 'resulting deficits later, naturally or artificially replaced. The purpose of the invention is year-round space heating and cooling, including hot water preparation, in an economically favorable manner and effectively saving fossil fuels.

It is well known that the state of the art of solar technology to overcome the difficulties is not yet fully developed. The very freshest sources known to me from this research area are: -

Hörster, H. and co-workers: Ways to energy-saving houses. (Report on the research project "Rational Use of Energy and Use of Solar Energy in Buildings") Philips GmbH, 1st edition, Hamburg 1980.

Matthöfer, H. and coworkers: Solar energy II, in the "Research Current" series, Umschau Verlag, 1st assignment, Frankfurt am Main, 1977.

Rudolph, R. and co-workers: Heat pumps for heating, cooling and energy recovery 1976 - 1990. Study carried out on behalf of the Federal Minister for Research and Technology, Bonn, from Battelle-Institut e.V., Verlag TÜV Rheinland GmbH, Cologne, 1979.

The worst dilemmas of artificial use of solar energy are ^:

the cloud-dependent instability of global radiation (all authors)

the daily and seasonal changes the supply of solar radiation energy (all authors)

the temporal reversal of supply and demand solar radiation energy (all authors)

the big losses with conventional long-term storage and the transport of heat (Hörster, p. 49 - 55)

the short life and high overhaul costs of current devices (Rudolph, 1979, pp. 23 - 25)

In the author's opinion, however, it should not be ignored that:

Firstly, the balance of the solar energy radiated in and out is so huge that the small loan for The needs of civilization cannot have any ecological significance - this relatively small amount of energy always becomes in the end radiated out to space and

Second, we have a practically limitless amount of radiation at our disposal, free, effective and gigantic Absorber, the water on the earth's surface (partly also deep down, so that we get those heat sources during the cold Season), and still the absorbed heat gets to us through movements of seawater, rivers, groundwater etc. transported for free, and

Thirdly, after the invention of heat pumps, it has become possible for us to heat lower temperature levels to one bring a higher temperature level.

From all of the above, we should draw the following clear conclusions:

The main focus of solar technology should be placed on indirect utilization, on extracting heat from the water.

If necessary, e.g. if there is a lack of running water or

There must also be space for large water supplies, direct Utilization of solar radiation can be put into use.

. Because the heat sources have a relatively low temperature, the heat pumps should be used both in utilization direct than indirect solar radiation and, in order to reduce costs, should be heat pumps more durable, cheaper and, however, more effectively developed. A practically lossless short-term heat storage and Transport is necessary in order to be able to take advantage of the very shortest direct radiation periods and the very smallest intensities, without the continuous operation of the heat pumps.

Likewise, the collected heat must be able to be stored for longer periods without significant losses, so that the seasonal Reversal of the heat supply and the demand

can be matched.

The invention is based on these objects.

According to the invention, the tasks are based on the following principles and solved by means of the means described in more detail in claims 1 to 4:

The solar radiation gives the water its liquid appearance, nature has therefore stored latent heat in the water. That warmth is always available to us when we artificially freeze the water in a storage tank A with a heat pump - and even 80,000 kilocalories per m.

Let us evaporate a liquid with a low boiling point by solar radiation in a storage container B. and if we then collect the gas containing latent heat, latent solar energy is available to us again, if the gas is liquefied by means of a heat pump to melt the ice and thereby be stored permanently. .-, ___ ..

It must also be possible to use _{both heat generation methods separately and independently.}

Because the storage is not in conventional pursuit high temperatures, but in the measuring temperature range (evaporation temperature of the liquid in question) takes place, and because the losses of the heat pump system are returned as heat are to be won, the losses are extremely small.

The aim is to reduce the construction costs and the service life of the devices' and reduce the losses "with a special heat pump design, some of which may already be known beforehand. In the literature, a brief note (Rudolph, 1979 p. 25) found on a heat pump cascade, without any report and with a comment: "However, they are complex and associated with correspondingly high system costs". In this invention it is taken for granted held that it is economically more favorable, instead of one, "according to the effect requirement alternately large compressor and Motors, several, identical, with smaller pressure and liter output to choose working compressors from series production for heat pump construction.

The term "heat pump cascade" is understood here a system of successively coupled heat pump circuits, each of which has its own suitable work equipment, and with which a gradually increasing temperature is reached. The effect of the overall system is determined by the number of side by side regulated cascades switched on as required. The heat losses are reduced by means of an explosion-proof heat recovery system from all devices in the heat pump system to preheat the gaseous working media flowing into the compressors used. The economy of the construction is achieved by reducing the wear between the pistons and the cylinders of the compressors and still through the use of the common motors for compressors of the same cascade and the straight heat exchanger for heat pump circuits of the same Order increased.

With the system conceived here, the difficulties listed at the beginning (pp. 1-2) can be overcome. Furthermore the following advantages should be noted:

Even the smallest amounts of energy from solar radiation, warm air currents, water condensation and ice formation on the The outer surface of the storage container B is kept (today's Roof collectors are only activated when there is a minimum irradiance of 50 W / m is exceeded, switched on (llörster, p. 29).

The devices, both the compressors and the heat exchangers, work under extremely constant conditions, practically independent of the time of day and time of year. This will be your optimal Dimensioning, construction and electrical control of their activities facilitated.

Where there is plenty of running water or space enough for a relatively large storage tank A, it is possible to use the storage tank B dispensed with and construction costs can be saved. If the ice is not climatized by lia during the summer and pre-cooling of the supplies is merged, it usually has to be removed in spring. Because the ice mostly the food industry, the fishermen, can be sold out for fresh water preparation in southern countries the exchange of the contents of the container no additional expenses ^

The use of an ice-water container, instead of the ground, does not endanger the water and sewage pipes or the building site, because no permanent frost can occur, the groundwater cannot suffer any damage as described (Rudolph, S ₀ 6 - 10)

Of the many possible embodiments of the invention are In the drawings some examples of the most important components and their use are shown schematically and in the following described in more detail.

Fig. 1 shows one of the most varied of mono- and bivalent Space heating suitable combination of heat recovery from water (A) and from direct solar radiation and air (B). For the sake of clarity, the parts are in different Rules drawn

Where there is a lack of fresh water, salty seawater is used as the heat source A, elsewhere pure water is preferred, from which the heat in the storage tank (1) is extracted with a flat heat exchanger (2) located on the floor and containing heat pump working fluid higher temperature level (approx. 333 ° K) is brought with the heat pump system (3) and fed to the space heating system (4 and 5). · After the specific heat of the water has been used and the temperature of the water has stabilized at approx. 273 ° K, ice begins to form on the surface of the heat exchanger (2), which would gradually be isolated without temporary ice separation. The easiest way to do it is with electricity, (not shown) the energy required for this is stored in the water * Because the heat pump circuit is blocked during the heating process, the pressure inside the heat exchanger is increased, this inflates and the upper, thin wall bends so that the melting ice formation breaks loose and rises upwards due to its small specific weight.

As long as the liquid of the space heating circuit (4 and 5) is not pure water, but e.g. water with frost protection is a second heat exchanger, useful a metal tube (6) required to bring heat directly from living spaces or heat from the heat pump system (3) to the ice-water

can. (If the heat transport medium is pure water, you can the flushing and outlet openings (7 and 8) are used). The various cycle alternatives are activated by means of the Electrically controlled all-way taps (9 and 10) selected. This will allow the transfer of the heat collected elsewhere from the Heat pump (3) for space heating or hot water preparation or for melting the ice in the storage tank (1). If the storage container (1) is used for watering the garden or as a swimming pool in summer, the ice will be in spring with the heating wires left in the container (not shown) dismembered and 'with the adhesive devices hung on the insulating cover and frozen solid during the winter (not drawn). Otherwise the ice will cause air conditioning Leave living rooms or pre-cool food supplies in the container.

The size of the storage container A (1) can be greatly reduced are collected, even if heat from solar radiation, warm wind, etc. with the storage container B (11 and 14) and for melting ice to the storage tank (1). The collector part (11) of the storage container B is made of, in a The liquid supply (12) located in a cool and dark place is almost completely filled by means of the feed pump (13). The liquid consists of two fractions, one (e.g. used oil from diesel engines) is thin, black in color and has one high boiling point and is easily soluble or miscible with the other fraction, which is a heat pump working fluid, preferably identical with the working fluid of the heat exchanger (2) of the storage tank (1) so that the same heat pump (3) can be used. At least the front surface of the collector part (11) is well permeable to radiation, so that in the black liquid fraction :! on absorbs the light, and as heat of the second fraction immediately is delivered. The latter is vaporized and the resulting gas containing latent heat is replaced by its own Pressure is directed to the storage part (14) located in the warm room »By evaporation of the working medium, the collector part (11) cooled down to the evaporation temperature (below 273 K), and automatically maintains this temperature if there is sufficient work equipment is conveyed from the heat pump (3) by means of the pump (15) into the collector part (11).

At the predetermined pressure in the storage part (14), the heat pump system (3) switched on and the gas brought through the line (16) from the storage unit to the heat pump. If the optimized electrical control or the mains power fails, the increased pressure drives the storage tank B (11 and 14) the liquid content through the automatically opened safety valve (17) and past the pump (13) in radiation and heat protection of the supply (12) .. This is the Collector part (11) protected from the extreme pressure that could result from overheating.

Because of the hydrostatic pressure, the working fluid is evaporated the slowest at the bottom in the collector part (11) and the upper one Collector part is best cooled down. An internal circuit is created in the liquid, which is connected to an external circulation pump (not drawn) can be supported. The fall of ice formation from the surface of the vertical standing collector part (11) is brought about with the electrical heating (not shown). The gas line (18) serves to equalize the pressure distribution between the supply (12) and the storage part (14).

2 shows a schematic floor plan of one of several identical compressors (19-26) and their common good insulated condensers / evaporators (27 and 28) built-up heat pump system.

From the heat exchangers located in various heat sources, the vaporized working medium of the 1st order is brought to the well-insulated short-term storage (29) through the lines (3Q and 31). If this memory is located outside of the semi-hermetic housing (32), for example with any of the heat sources, in a warm room (14, Fig. 1), it can be uninsulated. The pressure in the accumulator (29) controls the switching on and off of the three heat pump cascades, consisting of the motors (33, 34 and 35) and compressors (22 and 19, 23 and 20, 24 and 24) built in pairs on their axes, as required 21.). In the heat exchanger (27), the compressed gas gives the working fluid of the 2nd order its latent heat, is itself liquefied and turbid back to the heat exchanger in the heat source with the feed pump (37 or 36). With the working fluid of the

2nd order the compressors (22, 23 and 24) are fed. V / eil the energy transfer requirement of the 2nd order compressors with the primary energy of the first-order compressors has increased, additional compressors (25 and 26) switched on. In the heat exchanger (28), the working fluid of the 2nd order gives its latent heat to the water circuit (4 and 5) away.

Both the heat losses from all devices and the heat from subsequent cooling of the working fluid that has already condensed in the heat exchangers (39 and 40) must be recovered and on dearest in the heat pump systems themselves ingebrauchgenoraraen will. For this purpose, the semi-hermetic housing (32) has an independent heat pump circuit. An inactive, explosion-proof, Oxygen-removing liquid working medium is in close contact in the bottom sump of the housing with the heat exchangers (39 and 40), is evaporated and from .7ärme losses which further heats all devices. By means of its own compressor and heat exchanger (not shown) the Heat for heating the working medium of the 1st and 2nd order in the memory (29) and in the gas line (38).

Fig. 3 shows schematically the function of a simplified piston compressor with a vibrating cylinder (41) and a, piston rod (42) firmly assembled with the piston. Depending on whether the gas is exchanged with flexible hoses or is realized by the suspension of the cylinder, the latter (43) can be inside or outside the length of the cylinder. By changing the bearing distance (44), the liter capacity and the working pressure can be regulated will.

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Claims (4)

Patent claims: Storage of solar radiation heat, from which thermal energy is extracted by means of heat pumps, and the resulting deficits to be replaced later, characterized by that the containers of storage materials come in two forms ^ contain either solid and liquid or liquid and gas, and that the release of heat does not only come from the specific heat of the materials, but, even mainly, in connection with the transformation of the appearance of the Materials stands, and that the heat, which comes indirectly from solar radiation, is transferred to the liquid storage material with a working medium the heat pump (3) containing, located in the storage tank A (1), the fermentation exchanger (2) is withdrawn, so that the liquid turns into a solid body, and that the 7 / poor, which comes directly from the sun's rays the working fluid of the thermal pump (3) the gaseous state in a large collector part (11) of the container B (11 and 14) there, and the gas from it to the inside of the heated Space located storage part (11) of the container drives so that the gas can remain stored for any length of time in order to to be injected again into the collector part after the heat-emitting liquefaction, and that the last-mentioned collector part (11) of the container B is filled with two liquid fractions, preferably easily soluble between each other: the said working fluid of the heat pump and a thin, dark-colored liquid with a high evaporation temperature, the latter of which is good Radiant heat and "heat from" surroundings are absorbed and the former gives, and that the combined use of the two transformation processes, from gas to liquid and from liquid to solid Body that enables long-term protection of the direct radiant heat and thus the temporal reversal of the offer and can balance the demand for heat, and that the work equipment of the heat pumps is chosen so that the storage materials, during the activity, through the Withdrawal of the heat can be artificially cooled to a temperature, usually lower than that of the surroundings, and that the shape, the construction and the construction material of the storage tanks A and JB make them resistant to pressure, cold, make chemical and other harmful effects. 2. Storage container A according to claim 1, built of solid material with internal, surrounding reinforcements, thereby marked, that its walls have a small angle of inclination against that Point perpendicular and therefore the horizontal transverse area increases upwards (1), and that its walls against the earth up to the frost line of the ground have proper thermal insulation (not shown), and that its well insulated cover can be removed and that the ice formed can be removed by means of the fastening devices frozen in the ice after the ice has been divided into smaller pieces with electrically heated cable loops (not shown) _} and that the storage container has an electrically heatable heat exchanger containing the working fluid of the heat pump, and that the storage tank also has another heat exchanger, useful e.g. a metal tube (6) and two more Openings for the supply and return of the water (7 and 8), which enable artificial ice melting. 3. collector part (11) of the storage container B according to claim 1, marked you., that the front cover of the collector part is made of unbreakable, electrically heatable, well translucent material. is constructed, and that- the collector part (11) on, in the event of a power failure or has an automatically opening safety valve (17) in the event of malfunctions in the electrically controlled optimization systems of the activities, that enables rapid emptying of the supply (12), and that the collector part (11) -by means of a pump (13) of the supply can be refilled with the same or a different liquid. 4. heat pump according to claim 1, consisting of two or more, cascades connected next to one another, which are again composed of two or more heat pump circuits are indicated by the fact that all compressors (19 - 26) are the same among themselves, and that the effect of the overall system by the number of switched on Cascades is regulated, and that the number of compressors, in order to avoid bottlenecks in energy transmission, according to their ordinal number in the cascades increases (25 and 26), and that the compressors standing next to each other with the same atomic number also have common heat exchangers (27 and i? 8) can, and that the primary evaporator is outside the heat pump system, lie in one or more heat sources, and that working fluid converted into gaseous form either into a common, well-insulated supply (29) located inside the heat pump housing, or even better, in one outside of the housing, stored in a warmer environment (14) will, and that all compressors, motors and heat exchangers (39 and 4p) for cooling the various working fluids according to their Condensation in a semi-hermetic housing (32) are closed, where they are cooled by means of their heat loss an inactive, explosive-proof, oxygen-eliminating, cold gas is recovered, and with its own, expedient Compressor and heat exchanger (not shown) for preheating the gaseous working medium in front of all compressors Use is made, and that the compressors of the same cascades on the axis of the common source of power can be built, and that, as far as the compressors are piston engines, the cylinders are suspended within (43) or outside their length are that their axes are always parallel with the corresponding piston rod and the latter with the piston is firmly assembled without the piston pin, and that the change in the distance between the suspension of the cylinder and the crankshaft (44) is the fine adjustment the working pressure and the liter capacity of the compressor.