The invention relates to the method and system used to thermally treat ventilation air and has been designed to be used in the air handling systems installed in buildings, particularly in detached houses.

Modern and ecological buildings have walls well insulated with Styrofoam or mineral wool and windows with a very low thermal conductivity index, hi such buildings condensation furnaces are used to supply heat to the floor systems or radiators. Buildings, which are so air-tight, are hard to ventilate naturally, which produces stench, excessive condensation of "dew" on windows and tiles and even mould.

Air-to-air heat exchangers are used to prevent these unfavourable phenomena. The use of thermal energy removed with exhaust air to heat the supply air reduces ventilation heat losses by as much as 50-70%. It should be emphasized that ventilation heat loss in modern buildings, very well insulated thermally, is approx. 50% of total heat loss. The system distributing supply air to individual rooms ensures optimal ventilation of the entire building. An air-to-air heat exchanger is the main component of such a system.

Rooms are usually ventilated using air supply systems or air supply and exhaust systems, in which supply air is heated by a heater, which is heated by a stream of water heated in a gas or oil boiler to the temperature significantly higher than the target temperature of the air stream heated.

On the other hand, in systems in which supply air is cooled by the ventilation system described above, an air cooler is supplied with cool air produced by the ice water generator. The cooler is placed after the heater to protect it against freezing.

There are also air drying methods - ventilation systems as described above are equipped with an additional heater, usually an electric heater, placed after the cooler, and the air is dried by a stream of hot and humid ambient air passed through the main heater, which at that moment is inactive, and it is subsequently cooled in the cooler to the temperature of approx. 12-14°C and then heated to the target temperature of supply air (usually 16-18°C) in this additional electrical heater.

There is also an air heating and cooling installation operating in the way described above, in which the heat exchanger of the air recovered from the supply air stream is placed before the heater, hi this case the stream of hot and humid ambient air is first cooled with the cold air recovered in the heat exchanger from the exhaust air stream and subsequently water is condensed as described above. A typical and universally used ventilation system seen from the direction from which supply air is taken has the following components: heat exchanger, main heater, cooler and optional additional heater.

This configuration and the resulting air treatment method have significant drawbacks:

an air-air heat exchanger usually does not work in very cold temperatures because of icing and all the air because of icing must be bypassed; a bypass is used together with the exchanger and the entire load connected with the heating of icy air is taken over by the heater when at the same time the cooler, which is placed after the heater to protect it against freezing, is inactive; a rotational heat exchanger used to eliminate the drawback described above is more expensive and has another significant drawback - microorganisms in the exhaust air are rotationally transferred to the supply air stream; - in summer the main heater is inactive while the economically ineffective electrical heater is active and consequently thermal energy is supplied to the ventilation system in a situation when there is excess heat outside the building and in the exhaust air.

This invention aims to eliminate the drawbacks described above, in particular to:

1. considerably reduce the amount of heat supplied to the mam heater during cold temperature,

2. restore the functionality of the air-air heat exchanger during cold temperature,

3. eliminate the need to supply additional heat to dry air in summer,

4. reduce the costs of air cooling in summer by eliminating cool air production using ice water generator,

5. eliminate the non-ecological ice water generator from the air cooling process in summer, which consumes very large quantities of conventional energy to produce cool air,

6. eliminate the non-ecological ice water generator from the air cooling process in summer, in which an ozone depleting substance is used to produce cool air.

This invention suggests that the ventilation air stream flowing through the ventilation system is heated or cooled using at least one ecological thermodynamic medium obtained from a cold source of geothermal energy.

It is advantageous when the ventilation air stream flowing through the ventilation system is first heated by at least one ecological heating medium and when at least one of these media is obtained from a cold source of geothermal energy and subsequently this air stream is heated to the target temperature by a heating medium obtained by any known method, i.e. by converting photovoltaic energy in the heat pump compressor. It is also advantageous when the heating medium used to heat the building is first divided into at least two streams and then at least one of these streams is used for the purpose of target treatment by means of the heater in the ventilation system. At the same time it is advantageous when in summer the air stream flowing through the ventilation system is cooled in an eco-converter supplied from a cold source of geo- thermal energy.

It is also advantageous when in summer the air stream flowing through the ventilation system is passed through the eco-converter working together with the heat exchanger and/or heater where it is dried and the eco-converter is supplied from the cold source of geothermal energy.

Furthermore, it is advantageous when in winter the air stream flowing through the ventilation system is passed through a cascade of eco-converters where it is preheated; each eco-converter in the cascade is supplied from separate cold sources of geothermal energy.

The eco-converter, which is placed in the ventilation system and supplied from a cold source of geo-thermal energy, is functionally connected in series to the heater in the ventilation system, which is supplied from any heat source, preferably from a heat pump and/or any other source of thermal energy.

It is advantageous when the heater is a cascade of heaters supplied from separate sources of thermal energy.

It is also advantageous when the eco-convertor is a cascade of eco-converters supplied from separate cold sources of geo-thermal energy.

It is also advantageous when the heat pump is supplied from a source of electrical energy, preferably photovoltaic energy.

It is also advantageous when a buffer adjusting the parameters of electrical energy is put between the source of electrical energy and heat pump compressor.

It is also advantageous when an exhaust heat exchanger, preferably an air-air heat exchanger, is placed between the eco-converter and the heaters.

It is also advantageous when a recovery converter, which is supplied from any source of waste thermal energy obtained from the heated building, is placed between the eco-converter and heaters.

It is also advantageous when a recovery converter is placed between the eco- converter and the air-air exchanger and/or between the air-air exchanger and the heaters. A new configuration of heat exchangers in the system is used in the invention - a cheap geo-heat obtained from a ground exchanger is used to cool the air in the system during summer and to pre-heat the air supplied to the system in winter.

The economic effect resulting from the application of the invention is twofold:

- investment effect - elimination of the ice water generator containing CFC or a similar chemical compound, which is hazardous to the natural environment, as the working medium

- operational effect in summer - production of cold air in a conventional cold air generator, which uses large quantities of electrical energy, is completely eliminated; cold air is obtained from a ground exchanger of geo-thermal cold air,

- operational effect in winter - demand for thermal energy in winter is reduced; this effect is obtained when exchangers are installed in the following order: o first a converter supplied with geo-heat obtained from the ground exchanger, hereinafter referred to as eco-converter in order to emphasize its functionality, o main heater converter; it is advantageous to use a heat exchanger, particularly an air-air exchanger, between the first and second converter.

What should be emphasized is the unexpected ecological effect, resulting from the reduction of the energy dissipation processes - when ice production equipment (an ice water generator) is eliminated, heat, which was released to the atmosphere when cold air was produced, is eliminated.

The invention will be described in detail and illustrated in the figure with the following components:

- Fig. 1 - a block diagram of the system with the supply ventilation system,

- Fig. 2 - a block diagram of the system with a supply and exhaust ventilation system,

Fig. 3 — a block diagram of the system with a supply and exhaust ventilation system and a cascade eco-converter

In the examples described below different heat sources are used to supply heater (6), eco-converters (40, 4), recovery converter (10) and air-air exchanger (11):

1) heater 6 is supplied with the heat obtained from heat pump compressor 2, which, in turn, is supplied with heat from a geo-thermal source of eco-heat 51, by means of a ground heat exchanger, and with electrical energy from the source of photovoltaic energy 1 by means of buffer 7, which adjusts the parameters of the electrical energy; heater 6 can be also supplied from another source of thermal energy 8, e.g. from a heat boiler; 2) eco-converters 4 and 40 are supplied from separate cool sources of geo-thermal energy 5 and 51, e.g. ground exchangers; eco-converter 40 is supplied by means of distributor 12;

3) recovery converter K) is supplied from any source of waste heat 9, recovered from the heated building, e.g. from the thermal circulation of hot grey water,

4) air-air exchanger IX is supplied from the heat of exhaust air stream

Example I (Fig. 1)

The example shows the application of supply ventilation system 3 with heater 6, supplied with a heating medium provided by heat pump 2 and eco-converter 4, supplied from a source of eco-heat 5, i.e. ground exchanger.

Eco-converter 4 first heats the stream of cold atmospheric air to the temperature close to 0 ⁰ C and subsequently, in heater 6, the stream is heated to the target temperature, e.g. +18°C.

A recovery converter Jj) can be placed between eco-converter 4 and heater 6 in order to increase the temperature of the stream before it enters heater 6.

Example II (Fig. 2)

Air pumped by supply-exhaust ventilation systems 2 is first directed to eco- converter 4, which is supplied from a source of geo-thermal energy 5_, e.g. a ground heat exchanger. The quantity of heat supplied to eco-converter 4 is regulated by the efficiency of the pump, which pumps the cooling liquid between the eco-converter and the ground exchanger. When the air has passed eco-converter 4, it is directed to air-air exchanger H, which recovers the exhaust heat, and then to heater 6, to which any source of heat is connected, preferably heat pump 2 and/or another source of thermal energy 8, e.g. a central heating boiler with an oil or gas burner.

If the temperature of external air is much higher than the expected temperature of air supplied to the building, a liquid from the ground exchanger is pumped through eco-converter 4 with intensity proportional to the demand for cold air; the liquid obtained from the ground exchanger has a low temperature, approx. 5°C, which helps to cool the supplied air down to below 12°C.

If there is no need to dry air, the air cooling process is adjusted so as to get the target temperature of e.g. 18°C after eco-converter 4. If air is dried, typically at high temperatures and high humidity, which in Poland is observed between June and August, the stream of the flowing air is cooled down in eco-converter 4 to the temperature ranging between 12 and 14°C and subsequently this air is heated in air-air exchanger ϋ with the recovery heat, up to the set supply temperature. If the quantity of the heat recovered from the exchanger is too small or there is no exchanger in the ventilation system, dried air is heated using the main heater.

On the other hand, if the temperature of external air is higher than zero or lower than the set supply temperature, the air is heated in ventilation system 3 by the heat recovered using air-air exchanger 1_1 and additionally heated with heater 6 to the set supply temperature.

If the temperature of external ah" is about zero or less, the external air supplied to ventilation system 3 is first heated by means of eco-converter 4. In particular when the temperature is very low, external air is heated in eco-converter 4 from the temperature of e.g. -25°C to nearly O ⁰ C.

Air, first heated in eco-converter 4 is then heated as described above.

As before, in this case an intermediate converter 10 can be placed between eco- converter 4 and heater 6 in order to increase the temperature of the stream before it enters heater 6.

As a result of the thermal treatment of ventilation air suggested in the invention the cold air is heated by eco-heat to the temperature close to 0 ⁰ C and since the cost of geo-heat is very small the overall cost of treating air supplied to the ventilated buildings is considerably reduced.

Example m (Fig.3)

In the system described in Example 2 (Fig. 2) instead of eco-converter 4 a cascade of two eco-converters 40 and 4 is used. The eco-converters are supplied with eco-heat from geothermal sources £1 and 5_. As during intensive operation of the ground exchanger the working temperature of the stream of heating medium depends on the geo-heat supplied to that source of cold air, i.e. it is lower when more geo-heat is needed whenever cold air is supplied to it, the first eco-converter 40 in the cascade is supplied with the heat from source 5J., which is more intensively operated. In this application the heating medium from the ground exchanger is directed to heat pump 2 if the temperature is very low, and is subsequently pumped in distributor 12 and first gets to the first eco-converter 40, where it heats the stream of cold atmospheric air from the temperature of e.g. -20 ⁰ C to the temperature of approx. -5°C, thus relieving the source of geo-theπnal heat 5 which supplies the second eco-converter 4 of the cascade. In this way the second eco-converter 4 can have a ground exchanger with a lower heating power and can heat the stream of pre-heated air to temperatures above zero even in very low temperatures. The method of thermal treatment of ventilation air suggested in the invention allows for the heating of cold air with geo-heat to the temperature close to 0°C; the cost of geo-heat is negligible and therefore the overall cost of thermal treatment of air supplied to the ventilated buildings is also low.

In conclusion - a) the cost of supplying heat to the ventilation system in winter is not dependant on the severity of winter; it is at the level typical of mild winters, b) the cost of supplying cold air to the ventilation system hi summer is negligible, c) the cost of drying hot summer air is as small as the cost of its drying, d) the use of cold air does not require any use of CFCs or any other substance hazardous to the ozone layer; it is not connected with the heating of the environment, which, depending on the extent to which the invention is used, can significantly reduce the greenhouse effect.