GB2143026A

GB2143026A - Air heating and ventilating apparatus

Info

Publication number: GB2143026A
Application number: GB08227320A
Authority: GB
Inventors: Waldemar Hryniszak
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-09-24
Filing date: 1982-09-24
Publication date: 1985-01-30

Abstract

An air heating and ventilating unit comprises a heat exchanger 7a producing a small amount of hot air, a heat exchanger 6a producing a large amount of air preheated due to recovery of waste heat from the rooms 12 to be heated, both amounts of air being mixed at 11 to the temperature required for heating the room. <IMAGE>

Description

SPECIFICATION Hot air based heating and ventilating process The invention relates to a process where hot air is produced to heat as well as ventilate the rooms of a house, a building.

Known processes are based on producing a large amount of warm air, usually in periodical sequence.

Such process is not integrated with the recovery of heat wasted in the spent air when expelled to the atmosphere. This is especially true when it comes to the realisation of a combined process in a compact unit. As a result, large warm air producing appliances are required, the heat exchanging part of which is made from metallic materials. An additional separate appliance is needed if waste heat has to be recovered. Furthermore, in view of the relatively low temperature operation of the heating process, large amounts of air have to be circulated, and the duct size has to be considerable, this being a definite disadvantage up to now when it comes to direct heating of rooms.

The process, in accordance to the invention, avoids the disadvantages mentioned, and permits the construction of a compact integrated heating unit performing in a continuous way, heating and ventilation, as well as waste heat recovery from the spent air before expelled to the atmosphere.

Figures 1 and 2 illustrate in a schematic way, the process in accordance with the invention. Fresh air, its amount depending on ventilation requirements, is extracted either directly from the atmosphere or indirectly from within the house, such as the loft, where heat losses have raised the temperature of this air. As an alternative, or in addition, the temperature of the cold air can be raised in a heat exchanger (1) on its heating side (1a) i.e. the side where the heat exchanging media, the air, is heated) by the exhaust of the system, the spent air, before being released to the atmosphere in the cooling side (1 b) of the heat exchanger (i.e. the side where the media, the spent air is cooled). A filter (2) can be arranged, especially when very small channels are being realised in the matrix of the two heat exchangers (6, 7).The pressure of the fresh air is then raised in a compressor (4) to such an extent that the pressure losses of the system within the fresh air circuit can be catered for. The compressor can be driven by an electric motor (3).

The fresh air flow is then divided into two branches, the amounts flowing in these branches can be regulated by a valve (5). The larger amount of fresh sir passes through the heating side (6a) of the airpreheater (6). There the fresh air is preheated by extracting within the heat exchanger matrix heat from the spent air before being exhausted to the atmosphere. This takes place on the cooling side (6b) of this airpreheater (6). The by far smaller amount of air passes through the heating side (7a) of an air heater (7). By way of heat exchange the temperature of it is raised to a high temperature, its volume depending on the ambient temperature as well as heating requirements of the rooms.Then the large amount of warm fresh air coming from the airpreheater (6), its temperature being limited by that of the spent air extracted from the rooms is further heated by mixing with a small amount of hot air coming from the air heater to the temperature required for the different rooms (12a, b, c) of the house to be heated and ventilated. A distributor (11) with valves for both the hot and the warm air permits control of both amount and temperature of air going to a particular room.

The spent air is extracted from these rooms via a filter (13), if so required, by a compressor (14) driven say by an electric motor (15). This air is further compressed so as to cater for the pressure losses in the spent air circuit, very much as in the case of the fresh air. The flow of spent air is then divided by means for instance of the valve (16) into a small amount and a large amount. The large amount passes through the cooling side (6b) of the airpreheater, and by doing so transfers heat to the fresh air flowing on its heating side (6b) as already mentioned.

The small amount of spent air is further heated in a combustion chamber (8) to the required high temperature. A preferably clean gaseous fuel such as natural gas, its flow being regulated by a valve (10) provides the heat, and a system (9) is necessary to ignite the fuel/air mixture. The heat so produced is transferred in the cooling side (7b) of the air heater to the heating side (7a) of this heat exchanger, where the small amount of fresh air flows. The cooling side of the air heater can be followed, for instance by a water heater (17), the spent air flowing on its cooling side (17a) and the water on its heating side (17b).

Furthermore, before the spent air is expelled to the atmosphere, preheating of the fresh air can take place in the heat exchanger (1) as already mentioned, of special importance at very low ambient temperatures.

The main heat exchangers used, the airpreheater (6) and the air heater (7) are preferably of the contradirectional, parallel flow type with thin walled, small equivalent diameter matrices. At least the airpreheater, that means to say, the heat exchanger where the hot combustion gases transfer their heat to the cold fresh air is preferably made from ceramic material permitting operation at very high temperatures so as to reduce the amount of hot fresh air to a minimum.

Plate type matrices can be used for either (1) or both of the above mentioned heat exchangers.

The regenerative method of heat exchange can be used for either both or one of the side heat exchangers.

Drum or disc type rotors can be used for these types of heat exchangers. Circumflow matrices such as packed wire gauzes may be preferred for the latter type.

Figure 2 illustrates the use of a disc type regenerative heat exchanger where the matrix of the airpreheater (6) is integrated with that of the air heater (7). The annular outer disc section being preferably used for the airpreheater, and the inner disc section for the air heater. A gear (19) and an electric motor (18) can be employed for driving the disc but it is also possible to use one of the two electric motors, say for instance motor (3) for the drive of the disc.

The disc and the combustion chamber (6) with its fuel supply system (10) and its ignition system (9) can be integrated, and valves can be avoided by the choice of resistance within the required duct system, but especially that of the matrix. As shown in the illustration, in this particular case the warm fresh air leaving the airpreheater matrix, and the hot fresh air leaving the air heater matrix are mixed before entering the distributor (11 ) with the valves required to feed the rooms (12 a, b, c) of the house.

As also indicated, one electric motor only can be used to drive both the compressor (4) for the fresh air and the compressor (14) for the spent air, and as already mentioned, the same motor can be used to drive the disc.

Claims

CLAIMS A process of heating and ventilating the rooms of a building characterised by the following steps:

1. Fresh air, its amount depending on ventilation requirements is extracted either directly from the atmosphere or indirectly say from the loft.

2. Alternatively or in addition, the temperature of the cold air is being raised by exchanging heat with the spent air before finally exhausted to the atmosphere.

3. The pressure of the fresh air, after being cleaned is raised to such an extent that the pressure losses within the fresh air circuit can be catered for.

4. The fresh air is then divided if required in a controllable way into two branches.

5. The larger amount of fresh air is indirectly preheated due to heat exchange with a more or less similar amount of spent air before it is exhausted.

6. The smaller amount of fresh air is indirectly heated due to heat exchange with a more or less similar amount of spent air after its temperature has been raised by the combustion of a preferably gaseous fuel.

7. As in the case of the fresh air, the flow of the spent air is divided if required in a controllable way into two branches.

8. The larger amount of spent air preheats a similar amount of fresh air by way of heat exchange.

(see 5).

9. The smaller amount of spent air is heated by way of combustion, preferably of a clean gaseous fuel before exchanging heat with a similar amount of fresh air (see 6).

10. The pressure of the spent air, after having been cleaned is raised so asto cater for the pressure losses of the spent air circuit.

11. The exchange of heat between the spent and the fresh air can be either regenerative or recuperative.

12. The larger amount of preheated fresh air is then mixed with the smaller amount of heated fresh air before being distributed to the rooms of the house.

13. The individual amounts of preheated and heated fresh air can be mixed in such a way that the requirements of individual rooms with regard to the desired room temperature can be met.

14. The process in accordance with claims 1 - 13 is performed within one unit.