by this time there were two basic types of individual residential buildings : manors for all-the-year-round residing of tenants and the house (summer residence) for residing only during the summer period. From the technological point of view of the requirement to manors and holiday apartments considerably differ. As in holiday apartments live basically during the summer period, the difference of temperatures of a premise and external air is rather insignificant. Therefore external walls of small houses usually have small thermal resistance to a heat transfer from air of an internal premise to the external. As a rule, walls of summer garden small houses make of the facilitated designs. And in these small houses heating, as a rule, is absent.
Necessity of creation of comfortable conditions for a summer garden small house and during winter time obliges owners to use various variants of heating, and in quality teplogeneratorov furnaces on firm fuel are used basically. Except furnaces and fireplaces electroheaters (TENy, reflectors, electrofireplaces etc. can be recommended also.). In these cases it is not necessary to use water systems of heating as at negative temperatures it is necessary to merge water from system, and then again to fill with its water - the employment connected with certain inconveniences. To avoid them it is possible if to use as the heat-carrier a nonfreezing liquid - antifreeze. However it is necessary to reckon with that antifreeze is expensive enough and toxic .
As to a heat supply farmstead and country houses with all-the-year-round residing of tenants their devices should provide all complex of the conveniences given to city dwellers: heating, hot water supply, cooking possibility. At the same time the basic teplopotrebljajushchie elements of houses - systems of heating and hot water supply have some features in comparison with systems of heating and hot water supply - city residential buildings.
They consist in the following:
- as houses of farmstead type have small volume and accordingly small teplopoteri, them usually connect to the external heating systems served by a group or individual boiler-house with temperature of the heat-carrier no more 95 ° S.Prisoedinenie of room systems of heating to a heating system in this case it is possible to make without mixing devices in a kind elevatorov;
- whereas farmstead houses have one-two floor, in them, as a rule, it is expedient to apply the most simple one-trumpet system of heating;
- izza absence of regulators for small expenses of network water for joining to a heating system of a hot water supply it is necessary to use capacitor water heaters in which heating system water heats up local water through a surface of the coil placed in it (boiler rooms coppers).
To heating of low buildings now apply oven, water, electric and air heating.
Most absolutely electric heating , characterised by a number of advantages, including convenience of regulation of thermal loading, absence of bulky heating devices, high gigienichnostju. Unique, but often solving lack of electric heating - its dearness. Cost of unit of released heat at electric heating several times above, than at heat development in furnaces or coppers.
the Greatest distribution was received by water and air systems of heating. At an estimation teplotehnicheskih properties of heat-carriers solving indicators are the weight both volume thermal capacity and temperature. From the point of view of quantity of heat containing in unit of volume, water has huge advantages. For example, at usual for systems of heating water temperatures 80 ° With and air 70 ° With a volume thermal capacity makes:
Сv=рСg=975x1=975 kcal / (m 3 h°s);
Cv=(1.29 x 273 x 0.24) / (273 + 70)=0.25 kcal / (m 3 h°s)
I.e. The thermal capacity of water is more than air thermal capacity almost in 4000 times . Accordingly its volume expense necessary for heating of the same premise, in thousand times is less than air expense, owing to it much smaller section of the connecting communications transporting razogretyj the heat-carrier in the heated premise is required. Great volumes nagretogo air complicate its transportation and distribution on heated premises. Because of considerable diameters of dividing air lines the fan for transfer nagretogo air it is necessary to have near to heated premises that is connected with penetration into a premise of noise from the working fan.
At the same time air as the heat-carrier, has a number of advantages in comparison with water.
- First, it transfers heat in a premise directly , i.e. Without installation of heating devices. Getting ability of air is great, at the expense of high conventional ability effective heating of a premise is carried out.
- Secondly, it is not required devices of the water drain of the heat-carrier (air).
Advantages of air heating are estimated by the person for a long time. It is known that heating by hot gases was the first way of artificial heating of dwelling.
the Simple and ancient way of heating by fuel burning indoors adjoined to the central installations of water and air heating. So, in a Hilt based in X century BC in territory of modern Turkey, for heating of premises the system of tubes in which hot water from the coppers which are in cellars of houses moved already was at that time used. In Khakassia and many other places of our country floor heating with use of warmth of products of combustion of on-line burnt fuel was applied. The system of air heating created in Italy, is in detail described still Vitruviem (the end of I century BC). External air heated up in underground channels, preliminary heated-up hot gases, and arrived in heated premises. By the same principle premises of locks in Germany in the Middle Ages were heated.
development of heating technics was influenced by a kind of applied fuel . In a current of many centuries firm fuel (fire wood, coal) was used and heating installations adapted to its combustion. Numerous designs of the centres and zharoven, fireplaces and especially the furnaces which were widely adopted in Russia are known. Heating furnaces often apply to burning of firm fuel and now.
With opening of new kinds of fuel (natural gas, oil) are created heating installations and thermal stations for their burning with heating of the intermediate environment transferring warmth in premises.
In modern systems of air heating low buildings air heat up usually in kaloriferahteploobmennikah, furnaces in which heat is transferred to air through a wall by products of combustion of fuel or electric heaters. Nagretaja from within metal (or brick) a surface of a heater (furnace) is cooled outside, giving heat to air. Teplootdacha to air that above, than heat exchange surface there is more, therefore it is artificial increase a surface of heat exchange or increase speed of movement of air adjoining to a surface of the heat exchanger.
air Density at average temperature +70 ° With approximately in one thousand times is less than waters, therefore its heating up ability (heat transfer factor) is considerable (in 3050 times) less, than this indicator for water. Thus in ognevozdushnyh heaters (heat exchangers) there is a danger of an overheat of a dividing wall of the heat exchanger. To exclude this negative phenomenon, apply compulsory movement of the air environment in the heat exchanger by means of fans.
By the industry few fans with low productivity, unfortunately, are issued and consequently are in most cases applied ognevozdushnye heaters and heat exchangers in which the so-called natural draught arising at its heating is used. A lack of heaters with natural draught is the insignificant size of an arising pressure of air. It limits extent of distributive air lines and creates difficulties in distribution nagretogo air on premises.
the Specified lack of heaters with natural draught is not defining. The main reason of that air heating is still a little widespread in low buildings, consists in insufficient release of cheap and unproductive fans, and also in noise created by them. Besides, designs of the heaters developed by this time are provided only for burning of network gas or liquid fuel. Therefore the greatest distribution for heating of low buildings has received oven and water heating. And water movement in water systems can be carried out without application of pumps, using the natural pressure arising owing to cooling of water in heating devices.