DIY heating system design in a private house

Recommendation points

• Design objectives and baseline data
• Calculation and placement of radiators
• Boiler and its piping
• Connection diagrams
• Working with alternative types of systems

Why is it worth taking over the development of a heating system in your own home? Firstly, it is beneficial from an economic point of view, and secondly, a project drawn up with his own hand will give a complete picture of the work of each section of the system, its strengths and weaknesses..

Design objectives and baseline data

Before proceeding with the design of heating in the house, you need to clearly describe a number of tasks. In general, the project should give a detailed answer to questions of the following order:

• what type of system will be?
• what capacity of the heating unit will be enough to make up for the heat loss in the house?
• how to distribute the heat generated by it throughout the premises?
• how to place radiators and pipes so that they do not interfere with the arrangement of furniture and other communications?
• how to dissolve the system with minimal investment of materials?
• how to ensure system settings for different temperature conditions?
• how to make a heating system safe and easy to maintain?

Naturally, project development cannot start if nothing is known about the design object. First of all, descriptive documentation of the building is needed: floor plans, cuts in different section planes, explication of premises with their area and cubature.

The second part of the initial data concerns the thermal properties of the building. It is necessary to clarify the temperature regime for each room, calculate the heat loss of both the average value and in the coldest five days. When calculating heat leaks through enclosing structures, windows, doors, the nature of floors and adjacent rooms must be taken into account – the method is described in SNiP 23-02-2003 “Thermal protection of buildings”. According to these principles of calculating, it is necessary to determine both the individual heat losses in each room, and their share in the total losses of the house..

Calculation and placement of radiators

Having determined the amount of heat that needs to be put into each room, the choice of the type and number of heating devices is made. The easiest way is with electric heaters: their electrical power is almost equivalent to thermal (efficiency is close to unity). With heating on a liquid heat carrier, everything is somewhat more complicated..

Thermal output of water radiators is defined as the amount of heat that the radiator is able to dissipate into the environment. There are many factors that affect this value: the intensity of air convection, line length, temperature and type of coolant, and its flow rate. Radiator manufacturers indicate only approximate values, on average from 100 to 250 W per section.

In principle, with a house heat loss of about 8 kW / h, it would be enough to purchase 60–80 radiator sections and distribute them evenly throughout the house. The approach is only partly correct, you need to take into account other points:

• there is no practical point in heating rooms that are not in contact with the street, therefore, radiators are placed mainly on enclosing walls;
• heat loss in one room can exceed the loss of others by 1.5–2 times. The thermal power must be divided exactly in proportion to the heat loss, and not to the volume of the room;
• if it is permissible to maintain 16-18 ° С in the living room or kitchen, then in the bedroom it is necessary to keep 22 ° С, and in the nursery – 21-24 ° С.

Each battery requires piping, so the sections are installed in the most dense groups in order to save pipe fittings. On the other hand, the spacing of the radiators in the space provides a more uniform and efficient heating – you have to find a compromise between economy and efficiency. The easiest way to calculate is to divide the number of radiators for a room by the number of windows in it. But a certain set of sections does not always fit under the window sill, therefore, it is possible to install an additional heating device in accordance with functional zoning – at a resting place, for example, or next to a work table.

Boiler and its piping

For any heating unit, two parameters are of decisive importance. The first is the maximum generated power that the device can deliver when burning fuel or converting electricity. The second indicator is the energy conversion factor, on which the actual heat output from the device depends.

In gas boilers, losses can be up to 30%: due to an incorrectly tuned burner, most of the heat escapes into the pipe, and the draft from combustion sucks warm air out of the room, causing a rush of cold outside. Electric boilers give off all their power in the form of heat radiation with small losses (up to 2–3%). The greatest energy value is possessed by geothermal systems, which, instead of losses, provide an appendage of up to 200% due to the low-potential heat of the lithosphere..

Ultimately, it is the actual power of the boiler that is important – it should cover the heat loss of the house with a margin of about 15-25%. The coefficient of reliability is necessary both so that the equipment does not work for wear and tear, and in case of emergency situations, when it is necessary to ensure rapid heating of the entire dwelling.

Working with gas boilers is the most difficult part of the project. It is necessary not only to select a unit of appropriate power, but also to properly organize the removal of combustion products. To adjust the draft speed, it is recommended to install automatic dampers and smoke exhausters. The remaining heat can be collected by an economizer connected to the return circuit, and it is better to take combustion air not from the boiler room, but from the street or from the underground.

Heating with a liquid heat exchanger has another technical nuance – a description of the hydraulic system. It is necessary to draw up a level-by-level pipe routing scheme, determine the total displacement of the system, compensate for the expansion of the coolant with an expansion tank and determine the appropriate circulation rate. Further, according to the required heating efficiency in different zones of the dwelling, separate circuits with different circulation intensities and coolant temperatures can be organized.

Connection diagrams

It takes a lot of time to connect radiators in every room of the house. It is better if this time is spent with pencil and paper, and not with the accompanying damage to materials and labor resources. The layout of pipes and their connections must be thoroughly thought out.

Different types of connections have differences in the distribution of the total power. The most classic scheme is two-pipe. With a properly selected circulation rate, it ensures uniform heating of each radiator in the system and allows for individual adjustment.

A single-pipe connection diagram is, rather, a way of local grouping of radiators. For example, three radiators of one room can be connected in series by a pipe with the installation of a common thermostat and shut-off valves. But as a general case, such a connection is impossible..

1 – heating boiler; 2 – security group; 3 – radiators with diagonal connection; 4 – Mayevsky crane; 5 – expansion tank of membrane type; 6 – valve for draining and filling the system; 7 – pump

Leningradka is a separate type of one-pipe system in which the radiators are connected through a short-circuit tap. It allows for the possibility of regulation, albeit not as flexible as with a two-pipe system – when changing the thermal regime, you will have to readjust the regulators along the entire length of the wing.

The choice of a wiring diagram is always carried out taking into account the peculiarities of planning the premises. For example, with a large distance from the boiler room from residential premises, the radiators are fed with a Tichelman ring – an analogue of a two-pipe system that organizes well the trunk and distribution pipelines. The heating system built by a “star” with the use of a collector group has the maximum functionality and ease of adjustment. However, this option requires a significant initial investment..

Working with alternative types of systems

In the age of energy saving, such a heating concept looks more and more justified: to provide an overall minimum temperature with a central heating system, and then conduct local heating in areas inhabited by residents most often, for example, infrared heaters or an air heating system.

In such cases, you have to work with sources of radiant heating, and the principle of their operation is not always clear. But it is worth remembering the calculation of the heat balance, as the picture becomes clearer. When calculating, try to raise the desired temperature inside the house by a couple of degrees, and you can easily determine the lack of power in such a thermal regime. And knowing the performance of the device, it will be enough to simply calculate the time during which it will fill the room with heat with a shortage of thermal power.

As we said, electric heating is more efficient in terms of efficiency, but not all types are equally useful in practice. The nature of the generated heat is also important: the convector heats the air, and the objects inside the room are heated from it. IR heating, on the other hand, heats objects directly, the outflow of heat in this case is less pronounced.