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Patent Searching and Data


Title:
A METHOD IN A REFRIGERATION PROCESS AND A REFRIGERATION DEVICE FOR CARRYING OUT SAID METHOD.
Document Type and Number:
WIPO Patent Application WO/1986/005575
Kind Code:
A1
Abstract:
Process for and arrangement for a process to enable a cooling cycle to switch to two or several pairwise different temperature ranges for the evaporator-condenser, also with different temperature spans in between, whereby a programme controller (P) transmits signals initiating the change-over function in such a way that more or less cooling medium is taken from or passed to a coolant container (R2) connected in parallel with the condenser (K) in response to impulses from external transducers signalling that a lower or higher amount of energy should be given off by the cycle, and that when drying materials most energy is given off when the material is coldest and wettest at the start of the drying process and that instead the temperature is highest at the end, and that when utilising the system for heating it is now possible to select different suitable temprature ranges by means of the change-over function, which are adapted to the possible energy absorption and dissipation, respectively, and that defrosting can now be effected during continuous operation and utilisation for air conditioning becomes possible as also the cleaning of flue gases through moistening and electrical charging and following liquid condensation separation on the evaporator (F1, F2).

Inventors:
OESTMAN BJOERN R (SE)
Application Number:
PCT/SE1986/000112
Publication Date:
September 25, 1986
Filing Date:
March 14, 1986
Export Citation:
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Assignee:
F A BJOERN OESTMAN (SE)
International Classes:
F25B5/00; F25B45/00; F26B21/10; F26B23/00; (IPC1-7): F25B1/00; F25B29/00; F25B41/00
Foreign References:
FR2562644A11985-10-11
US2359595A1944-10-03
US2715317A1955-08-16
US2807940A1957-10-01
US3065610A1962-11-27
US3145543A1964-08-25
US3237422A1966-03-01
US3264838A1966-08-09
US3301001A1967-01-31
US4365482A1982-12-28
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Claims:
PATENT CLAIMS
1. Process A process associated with a cooling cycle characterised in that the degree to which the cooling cycle contains cooling medium can be varied so that two or several pairwise different temperature ranges can be obtained at the evaporator condenser. *& 2.
2. A process associated with a cooling cycle in accordance with patent claim 1 characterised in that, if the requirement of energy transmission from the cooling cycle to the energy absorbing surroundings is increased, the pairwise temperature ranges are shifted to an absolutely lower temperature range, and in that if the energy requirement further increases also the span of the temperature ranges is reduced as a result, on the one hand, of the upper value (of the condenser) dropping and on the other hand of the lower value (of the evaporator) increasing whereas the opposite events occur if the energy requirement is reduced or additionally reduced. A process associated with a cooling cycle in accordance with any of claims 1 or 2, characterised in that when drying materials the lower/lowest temperature pair range is used as the energy requirement is higher, which is the case when the material is particularly wet and cold, whereby also the air flow to the material is increased to a corresponding degree (in terms of energy) so as to be able to utilise the increased amount of energy given off and in that the said temperature range consists of the pair evaporator temperature and condenser temperature, whereas the temperature at' the evaporator is at least 10 lower than the initial temperature of the material and at the condenser at least 20° higher, preferably consisting of the pair +10°C/283°K and +50°C/323° , and when the temperature of the material has gone up by at least 10 , which is normally measured on the basis of the now moist air from the material, and preferably rises to more than +40 C/ 313 K a higher temperature pair range is utilised, and in that an increased output is achieved by also installing one or several additional heating elements downstream of the condenser and in that also the pairwise different temperature ranges can if required be imparted reduced or increased temperature spans. *& 4.
3. A process associated with a cooling cycle according to any of claims 1 or 2 characterised in that when used for heating, for instance in the case of a heat pump, a changeover function can be obtained"in*, respect of the pair wise different temperature ranges on the basis of a basic temperature range, which for heating accommodation advantage¬ ously has the values +55°C/328°K and 5°C/268°K at the con¬ denser and evaporator sides respectively, in such a way that both other ranges and other pair values can be attained inas much as an increased requirement exists for energy to be given off for heating or for enabling the absorption of energy at lower temperatures than that of the basic temperature range, and in that either an increase or a reduction of the amount of energy given off by the condenser may occur depending on the requirement of heatabsorbing surroundings, and in that control of the various ranges and spans is effected by a programme controller, which receives its impulses from trans¬ ducers sensing on the one hand a reduced or increased require¬ ment for the condenser to give off energy and on the other hand a reduced or increased requirement for the absorption of energy by the evaporator, the transducers transmitting their impulses in relation to the changes in the corresponding temperatures at the points in question, whereby the programme controller passes, to a corresponding extent, signals to the changeover function of the cooling cycle so that the appro¬ priate ranges are selected, the programme controller also transmitting signals to other external functions such as fans, valves etc. and also receiving impulses about which temperatures are to be obtained as a result of heating. *& 5.
4. A process associated with a cooling cycle in accordance with any of claims 1, 2 or 4, characterised in that as for storage of excess energy this takes place in one or several vessels connected in series, which are in energy terms connected through a tubular circuit with the condenser of a heating process, the said circuit being continuous and passing from the condenser to the first vessel and then on to the next vessel, and in that the tubular circuit has been filled with some type of heat transmitting liquid, for example water with possibly an addition of glycol, and in that in the course of storage the programme controller transmits a signal causing a higher temperature range, usually above +60 C/333 K, to be selected, whereby there is a possibility of storing energy in the vessel/s/, and in that as a consequence of the series con¬ nection the first vessel develops the highest storage temper¬ ature and the last vessel the lowest, which can be utilised for different types of secondary heating in the respective vessels, a feature which also increases the amount of energy which the condenser can give off, and in that if the opposite conditions obtain the programme controller transmits a signal causing a lower temperature range to be selected, whereby energy is accordingly transmitted from the vessel/s/ to the cooling cycle for further utilisation. A process associated with a cooling cycle in accordance with any of claims 1 to 5, characterised in that if defrosting is required at the evaporator, the programme controller transmits a signal causing a higher and suitable temperature range or a different temperature span to be selected so that the frost can be converted into liquid for drainage from the evaporator with a view to some type of collection, and in that the programme controller receives impulses from transducers which measure a possibly increased temperature difference between the temper¬ atures upstream and downstream of the evaporator, respectively, in which case impulses are received and signals transmitted until the difference has been reduced to a certain suitable value, and in that with special requirements the evaporator can be split up into one or several additional evaporators, which enables defrosting, which from the point of view of the cooling cycle is more efficient inasmuch as the cooling cycle can operate continuously in spite of the fact that some evaporator is being defrosted, and in that also better and quicker defrosting is hereby achieved inasmuch as the warm flow of /air/medium passing over the evaporators reaches the evaporator to be defrosted sooner than the other evaporator/s/ and in that with this defrosting method the severe changes in pressure do not occur in the various parts of the cooling cycle as take place with other methods, while at the same time also the possible operating time of a compressor within the cooling cycle is prolonged, and in that a pair of valves about the evaporator to be defrosted isolate it from the cooling cycle in response to a signal from the programme controller during defrosting, the programme controller also transmitting a signal causing the flow of /air/medium to be switched over the evaporator/s/.
5. 7A process associated with a cooling cycle in accordance with any of claims 1 or 2, 4, 5 or 6, characterised in that for air conditioning, for example of buildings, or any other possible cooling, where heating is required at certain other times, the programme controller transmits, in response to an impulse from one or some external transducers, a signal causing another suitable temperature range to be selected, where the range may for example be increased to +15 C/288 at the evaporator and to +80 C/353 K at the condenser, and in that the air which is to be cooled now passes, as a result of valves at the evaporator and condenser being switched, over, the evaporator instead prior to being conveyed to for example a building, with the condenser energy being utilised for storage of energy during relatively short or long periods of time, and in that the impulses passing to the programme controller are first transmitted when certain limit values have been reached, advantageously about +23024°«C/296297°K. A process associated with a cooling cycle in accordance with any of claims 1 to 7 characterised in that for purification of different types of gas the procedure is such that one or several evaporators are given a negative electric charge by passing an electric voltage through them, the gas to be purified first being humidified and then given a positive charge before passing one or several evaporators which makes it possible for the ribs of the evaporator to attract with particular ease impurities from the gas, whereby conden¬ sation takes place to liquid or frost depending on the temperature ranges set by the programme controller at the evaporator/s/ whereafter impurities in the shape of liquid and/or particles are removed to the collection vessel, and in that the evaporators of which there may be several have their temperatures adapted to suitable values enabling them to con¬ dense out different impurities, inasmuch as for example sulphuric acid has a different condensation temperature than hydrochloric acid, and in that also stepwise adjustments of different temperature ranges may be effected by the programme controller in such a way as to ensure that an accurate separ¬ ation of different types of impurity can occur, and in that when removing frost purification also takes place by stepwise defrosting of the evaporators connected in series at suitable temperature ranges related to the condensation temperature of the impurity, until all evaporators have been defrosted, and in that a particle filter can be mounted to the respective evaporator for special separation of solid impurities from the liquid, and in that when purifying flue gases in conjunction with the heating impurities can be collected on the spot so that no new and remote district heating systems are necessary, and in that at the same time the efficiency and life of the exist¬ ing heating system can be increased. *& 9.
6. A cooling arrangement for carrying out the process according to claims 1 to 8, which comprises a compressor, a condenser, a throttle valve and an evaporator, characterised in that a cooling container is connected in parallel with the condenser and in that upstream and downstream of the cooling container are provided shutoff valves, the functions of which are controlled by a programme controller.*& 10.
7. A cooling arrangement in accordance with claim 9 characterised in that in a normal and continuous operating position the valves upstream and downstream of the condenser are open while those upstream and downstream of the coolant container are closed, and in that in response to a signal from the programme control¬ ler initiating a changeover function so that more cooling medium takes part in the cooling process the valves downstream of the condenser and coolant container, respectively, change position so as to be reversed, i.e. in the present position closed and open, respectively, and in that in response to a signal initiating reduction of the cooling medium taking part in the cooling process the valves upstream of the condenser and of the coolant container respectively change position so as to be reversed, i.e. in the present position closed and open respectively, and in that the programme controller also trans¬ mits a control signal to the throttle valve causing it to open or close for the influx of cooling medium into the evaporator, and in that the changeover function depends on external require¬ ments for energy or temperature changes. *& 11.
8. A cooling arrangement in accordance with any of claims 9 or 10 characterised in that the arrangement has been so designed that defrosting of the evaporator/s/ can proceed without shutting down while the cool¬ ing process is in operation, which is effected by the programme controller transmitting a signal to the valves downstream of the capacitor and coolant container respectively to change position so as to be reversed, and in that the evaporator can be split up into two or several evaporators receiving amongst themselves different evaporation temperatures, and in that valves are arranged about the additional evaporators for closing one evaporator at a time for defrosting, and in that the programme controller transmits signals to the various valves and receives impulses to the effect that defrosting is necessary from trans¬ ducers located upstream and downstream of the evaporator/s/ and in that also the flow over the evaporator/s/ is switched over.
9. 12A cooling arrangement in accordance with one of claims 9 to 11 characterised in that various types of gas can be purified of particles and liquids therein by moistening the gas prior to passing the evaporator/s/ and also imparting to it a positive electric charge and in that the evaporator/s/ is/are given a negative charge, whereby the latter come/s/ to attract impurities for separation without the various types of impurity being mixed, and in that thereafter frost or liquid condensation takes place on the evaporator/s/ within the appropriate, corresponding temperature limits and collection can take place in a vessel possibly pro¬ vided with a particle filtering device.
Description:
A method in a refrigerationprocess and a refrigerationdevice for carrying out said method.

SPECIFICATION

General specification

For cooling objects and things use is generally made of some type of cold-furnishing process in accordance with Carnot's theories. Frequently use is made in this connection of an evaporation process using a compressor, which maintains a certain evaporation pressure in an evaporator and a condensat¬ ion pressure in a" condenser with the aid of a throttle valve for regulating the amount of cooling medium reaching the evaporator. In order to control the process use is often made of a pressostat which senses the pressure in the evaporator-condenser and this makes it possible via the work flow to the compressor, to main¬ tain the necessary process pressure. ,

With the present invention the advantage can be achieved that in the course of the process not merely one pressure is available at the evaporator and one at the condenser. This single pairwise temperature/pressure range can now be replaced thanks to a change-over function by the possibility of obtain¬ ing one or several pairwise, different ranges. This change-over function is due to the fact that the possibilities of freely to vary the degree to which a system contains cooling medium thanks to a coolant container connected in parallel for storing such cooling medium as does not take part in the process. In addition it is possible to vary both the condenser's and/or the evaporator's individual temperatures freely since both the com¬ pressor and the throttle valve cooperate in the coolant con¬ tainer's intake and discharge of cooling medium.

In the pertinent sketch No. 1 the compressor is designated with (C-M) , the condenser with (K) , the shutoff valve about it

with (b) and (d) , an optional conventional coolant container for collecting liquid with (R 1), one or several evaporators with (F), (F „) etc., shutoff valves about (F 2) with (f) and (g) , the throttle valve with (e), the programme controller with (P) , a flow valve for the flow over the condenser with (h) and another flow valve over the evaporator with (i), one or several additional heating elements downstream of the condenser with (E), the flow over the condenser with (1) and that over the evaporator with (2), the condenser temperature with (t.), the evaporator temperature with (t 2 ), the flow temperature upstream of

2 (F ? > etc.) with (t f ), likewise downstream of (F~ -) with (t f ) and likewise downstream of (F.) with (t f ) .

In the present invention one or several coolant containers

(R 2) have, in addition, been arranged parallel to the condenser but otherwise located in any desired position, as well as one valve (b .and d) upstream and downstream of the condenser, one valve (a and c) upstream and downstream of the evaporator, one programme controller (P) , which controls these valves, the throttle valve (e) and the compressor. To (P) have also been connected the temperature sensors (t-) and (t_) for sensing condenser-evaporator temperatures, and it is possible to con¬ nect other external transducers for measuring external para-

1 2 meters (t-, t-, t_ etc.), (h) and (i) etc. (F 2 has been located at the top in the direction of the flow of medium (2) during normal operation. The invention can also be implemented in such a way that the flow of medium (2) is moistened prior to passing through (F) , and (2) can be given a positive and (F) a negative charge so that (F) attracts the particles present in (2). With the present process and arrangement numerous unexpected advantages are obtained, for instance that a single cooling cycle can be made to work in applications where this was hither¬ to impossible, thus enabling entirely new working ranges to be attained by the invention. Also the degree to which energy can be utilised in different applications is surprising and it is

now possible to reach unexpected temperature ranges. Another very important result consists in the possibility of reducing the dimensions of a cooling system while in numerous cases existing drying or heating systems can continue to be operated with increased efficiency for a large number of additional years. Over and above this entirely new application it should be added that with existing applications such as cooling or heating considerable higher efficiency is achieved with the present invention.

Process with change-over function

For drying objects and things use is normally made of some type of drying chamber, drying cabinet, tumble dryer etc. All these types of dryer make use for heating of direct electric hot water heating methods using fans to blow in the air. In the 1980s drying chambers have in certain cases been equipped with a dehumidifier for condensing the water in the material, and tumble dryers have been equipped with a heat pump for heating. The present invention, the drying processor, combines these two principles in such a way that the energy and time requirements are reduced and new working ranges are made available.

This invention for drying various types of material is charact- erised in that two or several pairwise and different temperature ranges can be utilised, such a pair consisting of heating and condensation, respectively. At the start of the drying process use is made of a lower temperature range, and as the drying process proceeds higher ranges come into play. In this way it is possible to ensure a lower energy requirement at the end of the drying process and a higher one at the start. In a cooling process this means that in a lower temperature range more energy is given off than in a higher temperature range, i.e. the coefficient of performance of a cooling system is higher in the lower range and lower in the higher range. In the initial stage of the drying process the material is particularly wet and cold, and the enthalpy at a higher temperature is greater than if the material were not wet. By removing the moisture from the material at an early stage one causes a smaller energy requirement as such to result with such a drying process.

During operation in the lower temperature range the air supply from the condenser (1) to the drying material is increased, and at a higher range the supply correspondingly declines in terms of energy. It may be possible to ins al one or several additional heating elements (E) downstream of the condenser in

order to reduce the drying time further. The air supply (1) goes to a drying cabinet, drying chamber or other place where the material to be dried is kept. Once the heated and dried air has passed over the material to be dried, the air returns with higher relative humidity to the evaporator (F) for conden¬ sation of the liquid whereupon the drying process proceeds in a mannerjdee-jied suitable for drying laundry.

When drying for example laundry the drying process starts in the lower temperature range, which is the range in which the drying process requires most energy, the temperature being in¬ creased in steps as the drying process proceeds. The steps may advantageously amount to 5 until the highest range has been reached, which at the condenser should normally be +85 C/358°K and at the evaporator +25°C/298°K. The starting range is as a rule +10°C/283°K at the evaporator and +50°C/323°K at the condenser.

The initial temperature range for the drying process shall be such that the evaporator temperature is at least 10 lower than the material's own starting - mperature, *1 and that of the condenser at least 20 higher.

As the drying process proceeds the exhaust air temperature increases, and once it has been increased to a certain suitable extent, in the case of laundry as a first stage to +30 C/303 K or more, the programme controller receives an impulse from a transducer in the exhaust air flow (t-). The programme con¬ troller then signals that a higher temperature range is re¬ quired, and this causes the condenser and evaporator temper¬ atures to rise, which increases first the temperature of the incoming air and gradually also the temperature of the exhaust air. As a second or additional step the transducer (t-) can pass an impulse to the programme controller so that the latter sends out a signal requiring an even higher range. Once the drying process is completed and the material dried, a signal from the programme controller will cause the initial temper- ature range to be selected in readiness for new and wet material.

When changing from a lower to a higher range the programme con¬ troller also signals for the air supply (1) to the drying room to be reduced, whereupon valve (h) throttles the supply.

Depending On the type of material to be dried both the initial temperature ranges and the final temperature ranges will be different than described above.

If required the span of the temperature ranges, i.e. the difference between the condenser and evaporator temperatures, can be reduced or increased at a signal from the programme controller. This will cause additional energy to be given off or reduced, or if what matters are the temperatures, they are reduced or in¬ creased both at the evaporator and/or condenser.

For heating inter alia buildings use is made of so-called heat pumps, usually designed as exhaust air, open air or under- ground heat pumps. All are based on the cooling process in accordance with Carnot's principles and have a predetermined sphere of application. This depends inter alia on what the heat pump in question is to be used for, low or high temperature heating of e.g. incoming air or older water radiators on the con- denser side and the characteristics of the heat absorbing medium such as +20 C exhaust air or -20 C external air. A common re¬ quirement has been to try to achieve as high a coefficient of performance as possible, which can be done by providing for especially good working conditions in the cooling cycles. This however implies that if in actual practice for a certain time worse conditions occur than those predetermined it may occasion¬ ally not be possible to start the heat pump or the coefficients of performance may rapidly drop to 1.0, i.e. the heat pump does not yield any advantage at all as a result of its operation. The present heating process enabling as it does variation of the pairwise different temperature ranges makes it possible to select the working range in accordance with the actual conditions. In this manner it becomes possible to have the heat pump at all times operating with a positive yield (open air heat pumps) or to achieve a coefficient of performance exceeding 1.0 as the

temperature declines so as to make it possible to achieve a higher energy output across the condenser or to bring about an overall reduction of the time during which the cooling process is in operation by always being able to produce the most favourable working conditions. With the latter should also be included the possibility of storing ey ss energy, thus enabling longer con¬ tinuous operation of the compressor and as a result thereof reduced wear and a better overall coefficient of performance. The foremost characteristic of this heating process consists in the fact that thanks to a change-over function the pairwise temperature ranges can be freely regulated, upward or downward. The pair consists of the evaporator and condenser temperatures. Also the temperature span of the pair, the difference between the evaporator and condenser temperatures, can be varied in such a way as to cause the span to be reduced or increased. The change¬ over functions are controlled by the programme controller, which receives its control pulses from temperature transducers. The latter are placed inter alia in the open air, in an exhaust air duct of the building if available, within the building for ad- justing the internal temperatures and at any other suitable points.

When changing the temperature ranges or span the programme controller passes signals to the valves (a-d), which open or close depending on whether more or less cooling medium is needed for the cooling process. If a higher energy yield is required from the cooling cycle, i.e. - under otherwise equal external conditions - a greater amount of heat dissipated from the con¬ denser, the programme controller signals that valve (a) should open and (b) close until the corresponding lower condenser temp- erature (t.) has been reached. This causes the amount of cooling medium taking part in the cooling process to be reduced and means that a lower temperature range becomes the working range thus causing the coefficient of performance to increase. If it is re¬ quired instead to reduce the energy yield, the opposite takes place, i.e. valve (c) opens and (d) closes until the corresponding

higher condenser temperature has been reached (t.). In this case a larger amount of cooling medium will take part in the cooling •process. If any of the external conditions is changed, for in¬ stance if with an open air heat pump the open air temperature drops, the programme controller sends signals to valve (a) causing it to open and to valve (b) causing it to close until the lower evaporator temperature (t„) has been reached. This causes thus a smaller amount of cooling medium to take part in the cooling pro¬ cess and, as a result, the temperature range changes; if the same condenser temperature is required as before the span is accordingly increased instead. If any of the external conditions change in such a way that the open air temperature rises, the opposite occurs as far as the cooling process is concerned. If, for instance, especially difficult external conditions obtain, the programme controller can supply signals causing both the con¬ denser and the evaporator temperatures (t and t- to change.

Normally a basic temperature range is selected, to which the system switches in response to a signal from the programme con¬ troller when the operation of the heat processor starts or some other event occurs, provided that no impulses are reaching the programme controller directing otherwise. In principle one starting temperature range and one or several other ranges may be suitable as basic ranges. A basic range may be the normal working range for ordinary heat pumps, i.e. -5 C/268 K at the evaporator and +55°C/328°K.

In an uncontrolled operating position, with a certain random working range, the various valves (a-d) are set in such a way that (b and d) are open and (a and c) are closed. The throttle valve (e) is. controlled by the programme controller in such a way as to be open until a lower limit temperature at the evaporator has been reached (t._), whereupon it closes until an upper limit has been reached, when (e) opens again.

By means of different signals from the programme controller the cooling cycle may be imparted both other pairwise differ- ent temperature ranges and other temperature spans. These

different change-over functions can be made either independent of one another or take place in any desired sequence.

The various temperature ranges and temperature spans are changed in steps in accordance with a sequence determined by the programme controller, advantageously in steps of 5° - 10°.

The compressor (C-M) is controlled by the programme controller and operates as long as a lower switching limit at the evaporator (t-,) or an upper switching limit at the condenser (t.) have not been reached. Other external functions such as fans, flow valves, circulation pumps etc. will be controlled by the programme controller with a view to bringing about an energy balance.

In the various situations in which the heat processor is assumed to be it will normally be the case that from time to time there is a surplus of energy. In cases where there is insufficient energy use is often made of a heat pump to compensate the energy shortage. By connecting to a heat processor in accordance with the present invention one or several vessels connected in series and/or parallel, the excess energy can be stored therein by the simple method of filling them with ordinary water. When a short¬ age of energy occurs, energy is taken from the aaid vessels and it is not necessary to operate a heat processor equally often and for equally long periods. The transfer of energy from the heat processor to the vessels and vice versa should take place through a closed tubular circuit. The latter may be filled with, for example, water and/or addition¬ al glycol or some other suitable substance. The tubular circuit passes from vessel to vessel and gives off (takes up) energy as a result of which the first vessel in the series is imparted the highest heat storage temperature, and the last one the lowest. The transfer commences from the condenser and ends at the evaporator.

By for example designing the heat requirements of a building in such a way that in the first vessel warm water is heated and in the last hot water (for radiators) and water for heating incoming

air, the special advantage is achieved that a very low temperature is obtained for reheating- the condenser. This increases the attainable energy dissipation due to the cooling cycle and makes it possible to design the cooling arrangement with smaller dimensions.

To circulate the liquid in the tubular circuit a circulation pump having several speeds is provided, with the speeds being selected by the programme controller. Energy can be stored con¬ tinuously, and the storage energy which may be given off by the condenser is sensed by the programme controller, which increases the circulation if there is more storage energy, while reducing it if the opposite is the case, and this is effected by the change¬ over function switching to another higher temperature range or span. For defrosting the evaporator of a cooling arrangement the procedure may be such that if defrosting is necessary, the pro¬ gramme controller supplies a signal causing the cooling process to switch to a higher temperature range in accordance with the given requirement. For defrosting water it is advisable for an evaporator temperature (t„) to be selected, which is higher than

+0 C/273 K. The programme controller receives its impulse to the effect that defrosting is necessary as a result of temperature

2 1 transducers (t„, t f and t f etc.), passing their values to the programme controller, which compares them with those of the evaporator (t»). If the temperature difference between (t f ),

. . 1 2 measured prior to passing the evaporator, and (t-' ), measured after the said passage, is higher than a certain given value, an impulse passes to the programme controller. The latter emits a signal to order defrosting unless (t-,) determines otherwise. For example, as regards the evaporator of an exhaust air heat pump, the limit value must as a rule be higher than 2 before de¬ frosting commences. Defrosting ceases as soon as a set lower temperature value has again been reached, whereupon the cooling cycle continues in the normal way.

Where an especially large amount of liquid may be present, which could settle as frost on the evaporator, the evaporator should advantageously be subdivided into one or several stages (F 1 , F 2 etc.). These must then be placed in such a sequence as to ensure that the evaporator having the lowest temperature (t_) is lowest in the sequence. The latter then receives cooling medium from the next higher evaporator. During defrosting the programme control¬ ler emits a signal causing a higher evaporator temperature (t ? ) to be selected while at the same time the evaporator, which is to be defrosted, is locked out of the cooling cycle since the valves

(f and g) located around the particular evaporator which is in the process of being defrosted supply cooling medium only to the evaporator in operation. In the case illustrated in sketch 1 (F2) would be defrosted while (Fl) would be in operation. Since the very warm exhaust air first reaches the evaporator in the process of being defrosted (F2), which is not in operation, very rapid defrosting is achieved without any abrupt changes in pressure occurring in the tubing pertaining to the cooling cycle as is the case with reversible operation of the evaporator or condenser. Another advantage consists in the fact that a longer continuous operating time is attained for the cooling cycle since the cycle is constantly in operation, in spite of defrosting.. A third ad¬ vantage consists in the fact that, as a result of the other advan¬ tages, the colder evaporator can condense less liquid about itself since the warmer evaporator/s/ enable/s/ the liquid to condense without any frost developing. When defrosting the air flow (2) is rerouted in such a way that instead the air flow reaches the warmer evaporator/s/ last. As a rule the cooling cycle stops entirely, which is accordingly not the case with the present invention.

As regards air conditioning of for example buildings or other types of cooling, where on some occasions heating may be required and on some occasions cooling, this has been solved by changing the temperature range and span in response to signals from the

programme controller. Advantageously the temperature (t„) at the evaporator is selected at about +15 C/288 K and at the condenser (t.) to about +80 C/358 K. In the course of air conditioning the cooling air, i.e. the incoming air, passes over the evaporator and not as usual over the condenser with a view to cooling. The excess heat of the condenser is advantageously stored, if this is possible, but otherwise it is discharged together with the exhaust air. A temperature transducer located outside the building trans¬ mits an impulse to the programme controller if the temperature of the open air exceeds for example +24 C/297 K. A transducer located in an exhaust air duct transmits an impulse to the pro¬ gramme' controller if the internal temperature is higher than about +23 C/296 . If both these transducers transmit impulses, the programme controller emits a signal causing the system to switch to the higher temperature range. This is effected in the manner described above.

The present invention makes it. possible to store energy from e.g. air conditioning for later use, for example for some type of heating. This may be the case both during short periods of time (days) or long ones (months), depending on the capacity of the storage vessels.

Valves (h) and (i) respectively, are controlled by (P), (h) in order to reduce or increase the flow of medium over (K) with a view to energy dissipation, and (i) in order to reverse flow (2) and take care of any mixing and the amounts involved of e.g. external air and exhaust air.

To purify different types of gas the evaporator/s/ is/are/ charged with negative electricity while the flow of gas over the evaporator receives a positive charge. In addition a gas flow humidifier is installed, this being located upstream of the evaporator, which ensures better electrical conductivity and charging of the gas flow. This enables the evaporator to attract easily any dirt particles contained therein, which together with the humidifying liquid settle as frost/condensate on the evapor- ator. By installing several evaporators (F. , . ) it is

now made possible to bring about condensation or condensation with frosting of different types of dirt particles and/or pollutant liquids on the various evaporators, subject to the correct conden¬ sation or freezing temperatures, respectively, obtaining. If frosting takes place and not liquid condensation the change-over function of the process operates in response to a signal from the programme controller, suitable temperature ranges for operation of the evaporator being selected in steps until defrosting of the appropriate evaporator has been completed so that particulate and liquid impurities run off to a collecting vessel and so on until all the evaporators have been defrosted. This entails the advant¬ age that the various impurities can very easily be separated for possible recycling for other purposes. If required a particle filter can be fitted in conjunction with the evaporators enabling the particles to be separated from the polluted liquid.

If for example two or several purification steps are carried out it is possible to achieve, for example in the case of a domestic heating system based on oil, that the efficiency of the heating system on the one hand increases above 100 %, while on the other hand all previous air pollutions can now be trapped at the points of pollution. By using an installation embodying the present invention and as a result extracting more energy from the flue gases then it would theoretically be possible in an oil firing system, the extent to which efficiency of the heating furnace has in the course of time declined becomes dramatically less important. In practice this causes the life of the heating furnace to increase by several years.

Cooling processor with change-over function

A common and known cooling arrangement consists of a compressor, a condenser, a throttle valve, an evaporator and possibly a relatively small liquid collecting coolant container connected in series with one another. For controlling the operation use is generally made of pressostats, which by measuring pressure (= tem¬ perature) make operation of the compressor possible or impossible.

The present invention also provides for a coolant container arranged in parallel with the condenser, two valves (a and c) up¬ stream and downstream of the coolant container and two valves (b and d) upstream and downstream of the condenser as well as a programme controller (P) . The programme controller controls the valves (a-d) and the throttle valve (e) as well as the compressor (C-M) .

With a certain embodiment for special defrosting of the evaporator the arrangement is split up into two or several evaporators (F-, F_, etc.). Upstream and downstream of the evaporators in question (F„ etc.) two valves (f and g) are fitted.

Upstream of (F ), downstream of (F ? ) and (F.) etc. temperature

2 1 . transducers (t f , t-, t f etc.) are provided. A valve (i) is fitted for switching the air/flow (2) over the evaporator/s/.

For especially rapid heating one or several additional heating elements (E) are with certain embodiments fitted after the con- denser, and for changing an /air/flow above the latter a valve (h) . The said flow may consist of any as such optional medium, depending on the actual application of the cooling arrangement (heating of air, water, ground etc.).

The programme controller receives impulses from the temperature transducers and other transducers external to the cooling arrange¬ ment and transmits control signals, e.g. in steps, to all sections of the cooling arrangement and surrounding external units such as fans etc. which are affected.

The cooling arrangement is characterised in that with a standard design valves (b and d) are open and (a and c) are closed during normal operation. Throttle valve (e) is open until the lower switching limit temperature (t„) is reached, at which point the valve closes to open again when an upper switching limit temperature has been reached. If the programme controller trans¬ mits a signal to the effect that the energy requirement, i.e. the dissipation from the condenser, is increased, valve (c) opens and (d) closes until a corresponding higher condenser temperature (t.) has been reached. If the opposite is the case, i.e. if the energy requirement is reduced, valve (a) will open instead and (d) close until the corresponding lower temperature obtains. At a specially low temperature up to that about the evaporator the medium giving off heat passes the signal to the programme con¬ troller to increase the temperature span between (t-) and (t„) so that the evaporator temperature (t„) drops and if this is not adequate thereafter also the condenser temperature (t.). If (t-,) drops valve (a) opens and (d) closes, and if (t.) drops separate¬ ly valve (b) closes and (a) opens until the required temperature/s has/have been reached, during which entire period the compressor continues to operate. With cooling arrangement one or several ranges of basic temperature pairs can be used, and these can be set at the programme controller at, for example, when starting up the arrangement, when there is energy equilibrium or in other states.

In case of an embodiment involving defrosting the cooling arrangement may be provided with only one or with several evaporators (F or F. „). In order, with normal operation, to

1 ,Z,_5 switch to defrosting the programme controller transmits a signal causing an adequate higher temperature range to be selected, which in the case of"water is higher than +0 C/273 K.

With one special embodiment comprising several evaporators three-way-valves have been arranged both upstream and downstream of the evaporator (F„) and any additional evaporators, which when defrosting does not take place allows cooling medium in the cooling

cycle to pass first through (F„) and then through (F.). This causes (F„) to become colder. A flow of /air/medium passes over the evaporators in the direction leading first past (F.) and then past (F„ etc.). With defrosting, (F„) is cut out, by the valves (f and g) switching the cooling medium flow in the cooling cycle. If the flow of /air/medium is switched over at the same time so that (F_) is passed first, defrosting proceeds quickly, since the warm flow heats the ice until the ice drops away. The air flow may consist inter alia of mixed air obtained from both a building's exhaust air and external air. During defrosting the programme con¬ troller transmits a signal to prevent external air from being absorbed into the mixed air.

In order to purify gases from pollution in the form of particles and liquids the gas ist first moistened prior to pass- ing the evaporator and also given a positive electric charge whereas the evaporator is given a negative charge. This causes the evaporator/s/ to attract impurities which can be removed in stages as frost or liquid condensates from the various evaporators whereupon they flow to the collecting vessels.