- Heating as a necessity
- How to calculate heating
- Water heating at home
- What you need to know before creating water heating
- How to choose the optimal water heating scheme
- Installation procedure for a water heating system
- In custody
In this article: how heating systems work; how to calculate home heating; water heating – pros and cons; options for building water heating; how to choose the best heating scheme; elements of a water heating system, the procedure and rules for their installation.
Imagine January in the tropics – a soft breeze blows a bungalow permeable to all local winds, the sound of waves rolling onto a sandy beach is soothing … Peace and warmth, peace and no worries about heating in the January cold – all this is very good and even wonderful, just not there we are now, not in the equatorial part of the Earth. That is why we sweep aside “tropical” fantasies and worry about the upcoming serious frosts. While the households of the apartments are cutting off the telephones of the heating networks, keenly interested in when the heating season will begin, the owners of private houses should worry about heating themselves.
Heating as a necessity
An immutable axiom is that any premises in which people live or work need to be heated during the cold season. The classic and most ancient method of heating – fireplace or stove – is ineffective today, because the size of the premises is growing and there is not enough stove heat. Among the “working” options for heating housing are electric, air and water, according to the source of thermal energy, heating can be electric, gas or solid fuel.
The most costly from the standpoint of the wallet will be heating with the use of electricity, whether it be infrared heaters or systems with heating of the coolant with heating elements. In addition, electric heating requires a guaranteed and uninterrupted supply of electricity, which is impossible in principle, therefore it is used only as a backup heating option, and the main one is built on one of the combustible energy sources.
The classically built heating system consists of a heating boiler connected to radiator lines. The coolant heated in the boiler – it can be air, steam, water or antifreeze – enters the radiator lines and radiators, giving off heat to the air of the heated rooms, and then returns back to the boiler for reheating and entering the heating channels.
How to calculate heating
Heating needs directly depend on heat losses through walls, floors and ceilings, through door and window openings – when calculating the power of a heating boiler, you should find out what the heat loss of the construction and finishing materials from which this house is created. Until the fall of 2003, the thermal protection of buildings in the Russian Federation was designed according to SNiP II-3-79 *, since the fall SNiP 23-02-2003 standards have been introduced – study them and make a calculation in relation to your climatic zone.
To a greater extent, heat escapes through the external walls with almost all of its area in contact with the external atmosphere, heat loss grows with an increase in the temperature difference between the internal (indoors) and external (outdoor) – normal internal temperature, usually determined at 20 aboutWith heat, it is combined with the highest negative temperature of the cold season in the area.
For example, at -30 aboutWith the average heat loss of walls, depending on their construction materials, will be as follows:
- brick, 670 mm thick (2.5 bricks), plastered from the inside – 89 W / m2;
- brick, 540 mm thick (2 bricks), plastered from the inside – 104 W / m2;
- chopped, 250 mm thick, sheathed from the inside – 70 W / m2;
- from a bar, 180 mm thick, sheathed from the inside – 89 W / m2;
- from a bar, 100 mm thick, sheathed from the inside – 101 W / m2;
- frame, 200 mm thick, filled with expanded clay – 71 W / m2;
- foam concrete, 200 mm thick, plastered from the inside – 105 W / m2.
Average heat loss of enclosing structures at -30 aboutFROM:
- wooden attic floor – 35 W / m2;
- basement wooden floor (floor above the basement) – 26 W / m2;
- wooden doors, double, without insulation layer – 234 W / m2;
- windows in a wooden double frame – 135 W / m2.
The heat loss of a double-glazed unit will be lower with a larger internal gap between the glasses, filling the inter-glass space with an inert gas (for example, argon), if the outer surface of the outer glass is covered with a special coating for thermal protection.
To calculate the heat loss, it is necessary to calculate the exact area of the external (end) walls, floor, ceiling, window and door ceilings, multiply by the heat loss with m2 their constituent materials, then summarize the results.
Water heating at home
If in the countries of Europe and North America air heating is most popular, then in Russia there is undoubted leadership behind water heating – the small diameter of the pipes, the high heat capacity of water, the effective creation and maintenance of the required temperature regime in heated rooms. However, there are also disadvantages – the installation of the pipeline system for water heating cannot be performed without the subsequent overhaul of the premises themselves, constant heating of the coolant (most often water) in the heating system is required.
And woe to those homeowners who, having forgotten to drain the water from the heating pipes in winter, leave their home for a long time, leaving the hot water heating system at low temperatures – upon returning, they will have to solve the heating issue practically from scratch. most of the pipeline will be damaged. But – even draining water from metal heating pipes, it is impossible to rid the system of metal corrosion, because the presence of air will significantly accelerate corrosion processes.
What you need to know before creating water heating
Its integral elements: a boiler for heating the heating water; pipes supplying hot water to radiators with a diameter of 19-65 mm; cast iron, steel or aluminum radiators; expansion tank capacity, on average 30 l.
The design or, otherwise, the diagram of the water heating system can be:
- one or two-pipe, depending on the connection of the radiators with the supply risers;
- with vertical or horizontal risers;
- top or bottom wiring, depending on the position of the supply pipeline;
- dead-end or with a passing highway.
In a one-pipe system, there are no return risers and chilled water from the radiators flows back to the supply risers. Therefore, the water temperature in the radiators of the lower storey tiers has a lower temperature than in the heating devices located higher, which requires the installation of radiators with a large number of sections on the lower floors..
One pipe system
The circulation of water in heating devices and risers of one-pipe systems occurs due to the temperature difference, while heating can be organized in two ways: by adjusting the water supply to the upper heating radiators so that most of it flows through the riser to the lower floors; hot water passes through the radiators of each floor sequentially, starting from the upper one, while in this flow-through heating method, only cooled water enters the radiators of the lower floors. It should be noted that the second method is all the more ineffective, since it does not allow the installation of valves in front of the radiators, because closing any of them will completely stop the circulation of water in the heating system.
Despite the obvious inconveniences, including the mandatory upper distribution of the supply risers, i.e. the need for an attic space, one-pipe water heating systems are cheaper (less pipe consumption than two-pipe ones) and have an aesthetic appearance.
According to the position of the risers – horizontal or vertical – the first option is more economical, in which the radiators of one floor are connected to one horizontal riser. Compared to vertical risers, to which radiators of different floors are connected, horizontal risers are easier to install, less pipes are consumed. However, during operation in horizontal risers, the formation of many air locks is inevitable..
The upper and lower piping layouts differ in the method of supplying the coolant to the radiators on the floors: in the first version, hot water from the boiler flows through a vertical riser to the attic and only from there along the risers that supply it to the radiators; in the second version, the coolant immediately, i.e. from the basement, directed along the distributing risers. With any of the two wiring options, install the expansion tank only in the attic, at the highest point of the heating system.
In dead-end heating circuits, the rings formed by pipes in which the coolant circulates have different linear lengths – the longest circulation ring goes along the riser located farthest from the boiler, and the short circulation ring runs along the riser that starts near the boiler. Associated circulation lines in heating systems have equal lengths of rings formed by pipes and radiators, so the resistance in them is relatively the same. Circulating water systems are easier to set up because in the risers and radiators that form them, almost equal conditions are established. However, the operation of such heating systems requires forced pump circulation, and the flow rate of pipes during their construction will be higher.
How to choose the optimal water heating scheme
First of all, let’s conditionally divide private houses into three types:
- Type I, one-floor house, steep roof, with or without a basement;
- Type II, house on one floor, flat roof, with or without a basement;
- Type III, a house of several floors (from two), the roof is both flat and steep, there is a basement.
In houses of type I, heating systems with vertical risers will be optimal, since with horizontal wiring it is impossible to organize heating of the attic under a steep roof. Regardless of the presence or absence of a basement, a two-pipe water heating system with natural water circulation, top or bottom wiring, is suitable for such houses. If the house does not have a basement, then the boiler is mounted on the ground floor, and the wiring of the system can only be on the top.
Type II houses, in which there is or does not have a basement, are best equipped with a horizontal heating system, with the installation of a boiler in the basement if the latter is available. Considering the usually low height of the chimney in such houses (no more than 6 m), the choice of a gas or liquid fuel heating boiler will be the right one..
For multi-storey buildings of type III, a two-pipe scheme of water heating with vertical risers will be optimal, while the wiring can be both upper and lower. Alternatively, and for the sake of economy, in houses from two floors it is possible to arrange a one-pipe heating system, because in it, the gravitational pressure for the radiators of the lower floor will be higher than the two-pipe, but the temperature of the coolant is much lower. Immediately abandon the idea of a heating system with a horizontal position of the supply pipes – with it, it will not be possible to heat all rooms with high quality in Type III houses. Vertical risers will provide natural circulation of the coolant in the system, and the considerable length of the chimney (over 10 m) allows the use of a heating boiler on any fuel.
Installation procedure for a water heating system
The water heating system is planned from the location of its main element – the heating boiler, it should be installed before the final planning of piping. For the boiler, in accordance with the area of its lower plane, a concrete pedestal with a height of 40-50 mm is cast, which can be replaced with an iron sheet, on top of which an asbestos sheet is laid. After installation on a pedestal, we connect the boiler to the chimney channel, covering the cracks at the junction with clay (do not use cement mortar, it will crack during boiler operation!).
Important:ventilation is required in the boiler room, forced or natural! It will be convenient to equip the ventilation hole with a louver to regulate the air flow.
Important: the piping of the heating boiler (the entry of the main pipes into it) is carried out exclusively with metal pipes, regardless of the type of boiler! Only after, at a certain distance from the boiler, the pipeline can be led with metal-plastic pipes, but the inputs to the boiler can only be carried out with metal pipes.
Important:the diameter of the pipes introduced into the heating boiler must be identical to the diameter of the outlets from the boiler – it is strictly forbidden to use adapters!
Important:Despite the truth of the statement that the heating boiler should be installed in a basement, this statement does not apply to a gas-fired boiler – it is forbidden to install a gas boiler in a basement by fire safety regulations!
Having decided on the installation location of the heating boiler and installing it, we proceed to drawing the heating wiring diagram – carefully consider the location of the risers, coolant supply pipes and the positions of the radiators. The latter should be placed under the window openings – the ascending stream of warm air will heat the plane of the inner glass and frame, preventing the dew point from shifting and fogging. Please note that the more bends and long sections the heating system contains, the worse the coolant circulates in it. When planning the laying scheme, it is necessary to position the heating boiler as low as possible in relation to the horizontal center of the radiators – the water circulates in the system due to the difference in its specific weight between the cooled in the pipeline / radiators and between the one supplied through the main riser from the heating boiler.
The cross-section of pipes and the material from which they are made is selected in accordance with the amount of money allocated for the creation of heating (pipes can be steel, galvanized, metal-plastic and copper) and the total length of the heating circuit – the larger the cross-section of the main pipes in the system, the easier and faster it will be the coolant move through them. The diameter of the main main pipe connected to the heating boiler must not be less than: for steel, galvanized or copper pipes – 22 mm; metal-plastic – 26 mm. Distribution pipes must have a smaller diameter than the diameter of the main riser. It is better not to use polypropylene pipes – they will bend when laid horizontally at a distance of 5 m, more than two heating radiators cannot be connected to them. When laying the pipeline, slopes should be set in the direction of the drain – 5 mm for each running meter of the pipeline.
Before the start of installation work on the mains supplying the radiators, at the highest point of the heating system (the minimum height to the boiler is 3 m vertically), an expansion tank is set up with or without an overflow pipeline (depending on the tank design). Expansion tanks for water heating systems can be open or closed. The design of the first type is outwardly similar to a saucepan, into the bottom of which a small tube is introduced, connected to the heating circuit, a pipe is cut into it from the side, connected to the overflow line. For example, with a total heating area of about 100 m2 an open expansion tank with a capacity of 30 l is sufficient.
The expansion tank of a closed type, called an expansomat, has the shape of an oval or a ball and is divided from the inside into two parts – for liquid and for air. The separating membrane is flexible and, with increasing water pressure, bends, forcing air through the valve installed in the air section of the expansion tank, when the pressure drops, it returns to its original position, while air is pumped back through the valve. Unlike open-type expansion tanks, the closed type can be installed in any part of the heating system, most often it is mounted near the heating boiler, after the security group.
In front of the closed expansion tank, it is necessary to install a console safety group for the heating boiler, which includes an automatic air vent equipped with a shut-off valve, a safety valve and a pressure gauge. This set of fuses will promptly respond to an increase in pressure in the system to a critical one and reset it by releasing excess through the air vent valves.
The next step is the installation of the pipeline before, between and after the radiators, as well as the installation of the radiators themselves. Everything is relatively simple here – the pipe is brought out to the position of the radiator, the radiator is installed, the inputs and outputs are connected, respectively, then the pipe is led to the position of the next radiator, where all operations are repeated. During the operation of the heating system, it will be especially convenient if each radiator is equipped with a tap, which allows eliminating air congestion in this heating section. When laying a line with radiators, it is important to avoid the formation of sharp corners on the pipe – all necessary corners should be as wide as possible.
At the last stage, the heating circuit is closed, where it began – in the heating boiler. When entering the boiler, a filter is installed and, if necessary, a forced circulation pump (the filter is installed before the pump).
Important: at any, but the lowest point of the heating system, it is necessary to arrange a unit for draining-filling the coolant – in the event of repair work or when the heating system is shut down, it will be necessary to drain water.
The first start-up of the heating boiler after the completion of the installation of the heating system should be carried out only in the presence of a heating specialist – a real one, and not some “experienced” neighbor or work colleague.
Whether or not to heat the street is a private matter for every homeowner. Taking into account the ever-increasing prices for energy carriers, this occupation is becoming more and more costly – isn’t it easier to attract specialists or allocate your time for thermal insulation of your home? Thermal insulation of the end walls with extruded polystyrene foam from the outside or mineral wool from the inside with the exclusion or at least minimization of the number of “cold bridges” will reduce heat loss at times – you will feel this savings on your own wallet. And let the Sun do the heating of the street …