Designing heating systems for country cottages: how not to make mistakes

If you are building a country house or seriously repairing an existing one, already at the planning stage you need to take care of how the rooms will be heated in the cold season.

Proper design of heating systems in private residential construction is a guarantee of comfort in winter, rational use of resources and efficient operation of equipment.

In this material we will consider heating systems for a private house, tell you how to choose the best option and show how to design a heating system using an example.

Step 1 - heating circuit

The primary task in the design of heating is to determine the heating scheme. Single pipe and double pipe schemes are distinguished. Each of them has its advantages and disadvantages.

Think what is more important for you: cost savings, even heating or aesthetic component.

What is a single pipe design?

The one-pipe house heating circuit is a chain of series-connected radiators. The coolant of the required temperature enters the riser into the heating main.

It moves from one radiator to another, gradually losing some of the heat. Thus, the heating may be uneven.

When implementing a one-pipe scheme with an upper wiring, the main pipe is laid along the perimeter of the entire heated circuit above the devices and window openings. Radiators in this case are connected in the upper part, which in itself is not very aesthetically pleasing.

Both inlet and outlet, the radiator is equipped with shut-off valves. A temperature control head can be placed at the input.

In circuits with lower wiring, the pipeline passes below the heating devices. This option looks much better, but requires the mandatory installation of Maevsky cranes on each battery.

They are necessary for the removal of excess air from the top of the batteries formed as a result of the supply of the coolant from the bottom without first passing through an open expansion tank for degassing.

Advantages of one-pipe heating of a country house:

• saving on materials;
• simplicity of design and installation.

A relatively small number of pipes significantly affects the appearance of the heating system, which in most cases is laid in an open way.

In two-story and large cottages, it is better not to use such a scheme

Disadvantages:

• difficulty controlling temperature;
• the operation of each radiator depends on the state of the entire system;
• limited length, the ability to process the circuit with a length of not more than 30 m.

To provide the possibility of temporary or permanent shutdown of one or several radiators without stopping the system, a bypass is laid under each of them - a bypass pipe with a valve system.

Improvement schemes Leningradka connecting the battery by installing two or three shut-off valves allows you to turn off a separate device for repair without stopping the system and draining the coolant from it. Read more about arranging a one-pipe heating system in a private house Further.

Two-pipe heating model

A much more perfect scheme is a two-pipe one. The principle of its operation is the presence of two pipes - supply and return, to which radiators are connected in parallel.

When laying heating according to a two-pipe scheme, the radiator is connected to the supply and return, on both sides it is equipped with shut-off valves

The coolant flows through the supply pipe to each device with the same temperature. After passing the radiator, water enters the return pipe. Such a scheme can ensure uniform heating of the entire cottage.

Advantages of a two-pipe heating scheme of a country house:

• independence of devices from each other;
• uniform heating;
• the ability to control the heat transfer of each radiator using thermostats installed on the devices.

In addition to the relatively high consumption of materials materials and design costs, double pipe system heating has virtually no drawbacks.

Step 2 - the calculation and the architectural part

The architectural part of heating design involves the arrangement or construction of a room for equipment - a boiler house in a country house, as well as the choice and calculation of the chimney. To correctly design the power of the equipment, the diameter of the pipes, the volume of the coolant and other parameters, calculations should be made.

The calculation part does not require in-depth knowledge from the field of higher mathematics, it is enough to substitute the necessary coefficients in the formulas and use the calculator.

Designing a boiler house in accordance with all the rules

Before proceeding with the design of wiring and the purchase of materials, you need to choose a suitable location for the location of the heat generator. It can be a separate room in the house - a boiler room. If there is no extra room, you can build an extension.

For a gas boiler that will operate from a central gas pipeline, it is necessary to organize a boiler room in accordance with all the rules, because gas services strictly monitor the implementation of gas equipment operating standards. If the boiler is placed in the wrong place or with violations, the project will not be signed and it will be prohibited to use the boiler until the comments are removed.

A well-made boiler piping ensures unhindered access to all system components

Basic requirements for boiler houses in cottages:

• ceiling height from 2.5 m;
• room volume from 15 m³;
• the boiler house enclosures must have a fire resistance rating of 0.75 hours;
• natural light should be provided;
• ventilation required.

The location of the boiler depends on its power.So, if the power of the unit is 151-350 kW, it can be located only in a separate room in the basement or on the first floor, as well as in the annex. Boilers with a capacity of 61-150 kW are allowed to be located on the second or subsequent floors.

Devices up to 60 kW can even be in the kitchen of a country house, provided that there is a window with a window. We also recommend reading material on how to competently equip a boiler room in a country house.

Choose a chimney and determine the size

Another important detail in the design is the chimney. It will bring combustion products out. The main requirements that apply to chimneys:

• the fire resistance of the material should not be less than 1 hour;
• all joints and joints must be treated with fireproof materials;
• the chimney must be absolutely gas tight;

The cross section of the chimney is determined in accordance with the requirements of SNiP 2.04.05-91. The size of the chimney channel depends on the power of the heat generator.

According to the materials of manufacture, chimneys can be:

• brick;
• metal;
• ceramic.

The brick option is usually designed at the stage of construction of a country house. pipes are wall, pipe and root. The device wall option is possible only during the construction of walls of the building. The root and mounted type can be built both after the construction of the walls, and after the construction of the roof.

Disassembled chimneys look like meter sections. Joints must be sealed with flame retardant material.

Metal chimney is now used everywhere. Stainless steel is a reliable, durable material that is not afraid of hot combustion products. Modern chimneys are designed in the form of so-called sandwich systems. A stainless steel pipe is placed in the same, but larger diameter. The free space between them is filled with insulation, usually with basalt wool.

Ceramic chimney pipe is not used so often. Its main advantage is high heat resistance, and the main disadvantage is fragility. In addition, the ceramic chimney is quite heavy.

Designing a chimney is a crucial step. The size of the hole is one of the most important parameters. It depends on the performance and power of the boiler.

Average diameters of round chimneys:

• for boilers with a capacity of up to 3.5 kW - 16 cm;
• up to 5.2 kW - 19 cm;
• up to 7.2 - 22 cm.

When calculating the height of the chimney, the height of the roof and the distance from the chimney to the ridge are taken into account. If the pipe is located close to the top point of the roof (up to 1.5 m), the height of the chimney will be higher than the roof by 0.5 m. If the distance between them is greater (from 1.5 to 3 m), the chimney must be at least one level with the skate.

Calculation of the required system power

In order to calculate the heating system of a country house, you need to take into account several factors at once, these are:

• climatic zone in which the cottage is located;
• power source of thermal energy;
• sources and volume of heat loss;
• area and volume of heated premises;
• number of radiators and their size;
• the presence of insulation of walling.

To select the power of the boiler and heating radiators, use the following formulas:

M_to= S_room x UM_to/10 + 30%where:

M_to - boiler power;

S_room - area of ​​the room;

MIND_to - specific power of the boiler per 10 square meters. m. of heated area.

MIND_to Depends on the region. For Moscow and the Moscow region take the value of 1.2-1.5 kW. A margin of 30% will be sufficient for a single-circuit boiler. If a two-circuit scheme is supposed, it is necessary to add another 20% for water heating.

Thus, a 9 × 9 house in the Moscow Region can be heated by a single-circuit boiler with a capacity of: M_to= 81 x 1.5 / 10 + 30% = 16 kW.

Knowing the power of the equipment, you can calculate the minimum amount of water in the heating system of the cottage by the formula:

V = M_to x 15.

For the same house in the suburbs, the system will need to fill in V = 16 kW x 15 = 240 l of coolant.

Is circulation natural or forced?

When designing heating for a country house, you need to determine how the coolant will circulate in the system: under the influence of gravity or using a pump.

Due to the slight slope of the pipeline, warm water from the boiler tends to go up and moves through the pipes, while the cooled water goes down. Thus, the system becomes completely autonomous

The natural way is good because the system does not require electricity. The circulation is carried out due to the physical properties of the liquid when the temperature changes.

The disadvantages of a system arranged by this principle:

• need more coolant;
• pipes should be larger in diameter;
• a slope of 2% must be observed.

In addition, to balance the temperature in the network with natural circulation it is necessary to increase the number of sections of batteries located farthest from the boiler.

If you are planning a system with forced circulation, the boiler room must be supplied with power for the pump exactly at the point where it will be located according to the project

Forced circulation works with a much smaller amount of fluid and the diameter of the pipeline, the slope is not required, and the choice of radiators is significantly expanded.

However, for full functioning, it will be necessary to equip the system not only with a pump, but also with measuring instruments and an expansion tank. All this should be taken into account when designing the system. with forced circulation.

Step 3 - choosing an energy carrier

The basis of the entire heating system is the boiler. Depending on the type of fuel used for heating, 4 categories of boilers are distinguished:

• solid fuel;
• diesel;
• gas;
• electric.

Having learned the main characteristics of all types of thermal energy generators for a cottage, you will not be mistaken in choosing the right option.

Solid fuel - proven method for centuries

For country cottages often choose solid fuel models boilers. This is primarily due to the availability of raw materials.

A solid fuel boiler can work not only on coal or firewood, but also on wood processing waste, pellets, briquettes, peat, even on organic fuel from manure. The main thing is that there was where to store the entire supply of fuel. As for the efficiency of solid fuel systems, it is quite low - about 75% on average.

Modern solid fuel boilers are compact in size and presentable, but require the organization of a boiler room in accordance with safe operation standards

Another advantage of this boiler is its ease of use. In addition, when using solid fuel, the system heats up very quickly, which is important for suburban cottages. But at this heating rate, you have to constantly add fuel to the furnace, otherwise the system will soon cool down.

When buying a solid fuel model, be prepared to load it every 4-5 hours. With the same frequency you will have to clean the ash pan from soot and ash.

What warms a diesel boiler?

Diesel boilers run on light heating oil - a variety of diesel fuel. It differs from automobile DT in that the requirements for its quality are not so high, but such fuel is cheaper due to the lack of toll.

To use a diesel boiler, you need to install a tank for diesel fuel, a volume of at least 750 liters. You can imagine how much space he takes in the boiler room.

Diesel boilers are relatively bulky and noisy, but in a separate boiler room they will not create inconvenience

Of the advantages of this type of heating, the low cost of equipment, automatic on and off are distinguished. But to leave such a system unattended for a long time is undesirable. Another disadvantage of this device is the noise during operation.

Environmentally friendly electric heater

It would seem that using electricity to heat a country house is a simple and cost-effective solution. But here everything is not so simple. The fact is that the total power of the electrical equipment that you can install in your cottage is limited by the energy supplier.

Look at the electrical panel. Suppose a current of 16 A is indicated. Knowing the voltage in the network (220 V), you can calculate the allowable power.

16A x 220V = 3520W.

3520 W - maximum allowable power. This means that a boiler with a capacity of over 3.5 kW is not suitable for your country house. It remains only to write an application for permission to install automatic machines of greater power. The electric boiler can be connected to a conventional outlet, and can operate on a three-phase current (380 V).

The electric boiler does not create noise and does not pollute the environment at all. This is the only type of heat generator that does not need a chimney and a separate room

Advantages of an electric heating source:

• autonomy (does not require constant monitoring);
• automatic temperature support;
• no chimney needed;
• environmental friendliness - no products of combustion;
• ease of use.

Of the shortcomings emit high energy consumption. We also recommend that you read our other article, which describes the system in detail electric heating.

We use blue fuel - gas model

A gas boiler is one of the most common and widely available on the market. It runs on natural gas, can be connected to a gas pipeline or cylinder, if the gas is imported.

For liquefied gas in cylinders, this type of boiler is not the most convenient. One 50-liter cylinder is enough for 1-2 days of heating a country cottage.

A modern gas boiler can become a decoration of a boiler room - the design of some models is pleasing to the eye

There are single-circuit and double-circuit gas boilers. The single-circuit boiler is designed purely for heating the room. In the dual-circuit there is also the function of preparing hot water - it acts as a gas column. If you plan to periodically live in your country house in the winter, then it makes sense to install a double-circuit boiler.

But if in the cold season you will be absent for a long time and turn off the boiler, it is better to purchase a single-circuit. The experience of many users shows that it is difficult to drain the water from the system for temporary preservation in double-circuit models, part of the water can remain in the system, which is very dangerous and threatens with freezing and cracking of pipes.

Step 4 - Other System Components

In addition to the heart of the cottage heating system - the boiler, it also includes other equipment. Correctly designing a circulation pump, expansion tank, radiators or coils for underfloor heating and piping material is no less important than choosing the boiler itself.

Therefore, do not neglect the detailed study of the characteristics of additional equipment and the subtleties of its choice.

Pump - where to embed it?

Designing a forced circulation heating system requires a pump. For country houses, as a rule, wet circulation pumps are used.

When choosing a pump, the following parameters should be considered:

• pressure;
• performance;
• operating conditions (room area, selected coolant, type of connection, pipe diameter);
• additional aspects (noise level during operation, unit dimensions).

When designing heating in your own country house, it is important to find the most suitable place in the circuit for connecting the pump. By and large, a properly selected pump will equally well cope with its task on any part of the system.

The reason why it is recommended to be installed in front of the heat generator — on the return line — is because equipment is less worn when pumping water at a relatively low temperature.

The wet-type pump does not need to be lubricated - during operation, the impellers and bearings are lubricated with coolant. Cooling function also on it

For reliable pump operation during design, it is important to take care of the filter. The coarse filter is installed immediately before the pump. It picks up particles that have fallen into the water in the heating circuit. If you ignore the installation of the filter, the pump can quickly fail.

Safety group and expansion tank

Since the heating circuit is a closed system, and the water tends to increase in volume when heated, an expansion tank must be designed in the heating system of a country house. When the pressure in the pipes rises, excess coolant enters the tank, thereby reducing the dangerous pressure.

Safety block - a set of three devices that ensure reliable and safe operation of the entire heating system of the cottage.

These include:

• manometer - for measuring pressure;
• safety valve;
• air outlet.

There are no questions with the pressure gauge - it should be designed to measure the pressure of 2-3 atmospheres. That is a 4 atm pressure gauge. will be just right. The safety valve performs the same function as the expansion tank, but in emergency cases, when the tank, for some reason, did not work.

At a critical pressure increase, excess is removed from the system through the valve drain.

The branch of the pipe in the form of a trident on the left is the safety group. And the red tank on top is the expansion tank

The air vent must protect the boiler from accidentally entering the air heating circuit. Since air bubbles in the water rise up, devices for removing excess air are installed at the top of the riser or of each battery.

Piping and radiators - calculation and selection

The next step is to determine the pipe material for the heating circuit. Options may be as follows:

• steel;
• polypropylene;
• metal plastic;
• polyethylene.

Steel pipes used to be used for heating country houses. They are durable and not afraid of high pressure. Their main disadvantage is susceptibility to corrosion. Rust can penetrate steel through, fistulas appear in the pipes and the whole system becomes unusable.

Due to corrosion deposits on the inner surface of steel pipes, clearance decreases over time. And for their installation you will need at least a qualified welder.

The weak point of any pipeline is connections. When designing a heating circuit made of polypropylene, you need not worry about this. The pipes are connected by welding - a special soldering iron. Joints are monolithic.

Polypropylene pipes they are not subject to corrosion, they are practically not polluted from the inside, durable, light and inexpensive.

Fittings for polypropylene pipes can also be manufactured without the use of metal. This makes them cheaper, and is well reflected in the quality of the connection.

Plastic pipe sold in long coils - up to 500 m. Thus, it is possible to avoid the connection of the pipeline from individual parts by laying plastic pipes along the entire heated perimeter of the cottage. They also do not rust, nothing is deposited in them, they are durable. But you need to protect the metal-plastic pipes from UV rays and damage during installation.

Polyethylene pipes Use for hot water supply, heating and the device of a warm water floor. They have the same advantages as others, and their main disadvantage is the high cost of the pipes and fittings themselves.

Which is better - a radiator or a warm floor?

In a country house, sectional, plate or panel radiators are used as a heat radiator.

Such batteries may be:

• cast iron;
• aluminum;
• steel;
• bimetallic.

Cast iron batteries very heavy and fragile, but give off heat well. Aluminum models are light and inexpensive, but chemically unstable, corrode and fear pressure surges. Steel batteries also suffer from corrosion, but are chemically resistant.

Bimetal type batteries combines the advantages of aluminum and steel radiators. The coolant moves in a steel pipe and does not come in contact with the aluminum casing. This option is suitable when using antifreeze, rather than water in the circuit.

In this case, the radiator is connected to the horizontal wiring. Polypropylene pipes located under the floor are used. The pipes are insulated

Batteries are located under the window openings - in places where the wall cools the most. As a result, fogging of glass and the occurrence of condensation on the walls can be avoided. The number of radiators depends on the number of openings, but not less than 1 per heated room. Read more about calculating heating radiators here.

During the construction of the cottage, it is relevant to design a warm floor for space heating.Water heated floors are pipes laid under the floor, which are part of the heating circuit. This design is very effective.

It is necessary to design a warm floor together with the entire system and take into account its presence when calculating the boiler power and the number of radiators.

Features of the choice of coolant

The coolant is pure water or antifreeze. Water, of course, is cheaper and more affordable. It has a high heat capacity and copes well with its function. However, which is especially true for country houses, when the boiler stops, there is a risk of freezing water inside the system and damage to the pipeline.

For such cases, it is possible to design a system with antifreeze as a coolant. It does not freeze, has good fluidity and heat capacity. However, it is an environmentally unsafe substance. Drain it into the sewer is prohibited. Most boilers are not designed to work with antifreeze. And besides all of the above, antifreeze is also an order of magnitude more expensive than water.

Use coolant exclusively designed for this purpose. It is unacceptable to fill the car with an “anti-freeze” in the system, you can run into a fake and pour some unknown aggressive substance, acid, for example, into the heating circuit

Step 5 - wiring design + examples

The assembly of the pipeline can be performed in several ways:

• tee type assembly;
• collector.

The second name of the collector connection is beam. A collector is connected to the boiler, and from it pipes under each floor diverge to each of the radiators.

For heating a one-story house, a collector with 6 inputs will be enough. If the cottage is two-story, it is better to install a collector twice as much

A collector circuit is implemented using flexible metal-plastic pipes. After laying the flooring materials, all heating pipes are completely hidden and do not spoil the appearance of the room. Entrances and exits to each radiator are led from below directly from under the floor.

The tee connection is made through the connection by tees of all heating devices to the supply pipe and return pipe. It is simpler to implement such a scheme, no need to spend money on collectors and look for a place to install them, which is usually done in the center of the building to equalize the length of the rings connected to the comb.

In order not to reinvent the wheel, you can use one of the typical distributions of heating for a country house, which are successfully used in construction. The traditional single-tube model is well shown in the following drawing.

The drawing shows a small suburban, in which a single-pipe system will be quite enough

For a typical cottage, a combination of one and two-pipe schemes is often used. In this case, the wiring diagram looks like this.

The first part of the pipeline looks like a single pipe and only in front of the first radiator is it divided into two

The same house can be heated with a collector circuit.

In this case, a collector for 4 rings connected to one heat generator is enough

In this diagram, a separate branch departs from the boiler and leaves on the porch of the house. This is a heated step to prevent the formation of ice.

The main part of the circuit is a two-pipe system, while the additional branch is a single-pipe system.

In this case, the system provides for a separate pump, tank and safety unit for a single-pipe branch to the warm floor in the vicinity of the steps

In the following diagram, the heat pipe has bends in each of the rooms. That is, each room is heated by a separate circuit.

The pipes will need several times more, but the valves and thermostats on each branch allow you to adjust the temperature in each room individually

Conclusions and useful video on the topic

The video shows the basic methods for connecting radiators, describes the advantages of each of them:

This video material describes in detail all the nuances that should be considered when choosing heating pipes:

And here is a good example of designing a combined system for heating a two-story cottage:

Since the heating system of a country house should be primarily reliable and efficient, maximum attention should be paid to the development of the project. Any unaccounted detail can adversely affect the heating performance. Better entrust the design to a professional to avoid mistakes.

If you have already had to independently design and equip a heating system for your home, and you know the subtleties that you must pay attention to, please share your knowledge and experience with our readers. Leave comments in the block below.