Gas consumption for heating a house of 100 m²: features of calculations for liquefied and natural gas + examples with formulas

Saving electricity at the stage of calculations

Despite the fact that electricity has a high cost, heating with an electric boiler is considered the most efficient and economical. It is possible to save electricity consumption for heating a house by adjusting the operation of the device depending on changes in air temperature outside and the purpose of a particular room.

It is a well-known fact that the distribution of loads between consumers of electricity for 24 hours is uneven. For this reason, in order to maintain the required temperature without problems, it is desirable that the boiler unit mainly works at night (from 23:00 to 06:00). It is during this time period that the minimum electricity consumption is fixed, for which reduced prices apply.The use of multi-tariff accounting allows subscribers to save about a third of their financial costs. By the way: as practice has shown, peak loads occur in the morning from 08:00 to 11:00 and in the evening from 20:00 to 22:00.

There is a way to achieve maximum efficiency of the heating system. To do this, install a circulation blower. The pump is connected to the return network in order to minimize the time during which the boiler walls are in contact with the hot coolant. As a result, the heater has a longer service life.

Electric heating at home is attractive due to the absence of combustion products, noiselessness and safety in terms of ecology. It is rare that the owner of his own house does not think about the construction of such a system, especially if the area is not gasified.

However, knowing that electricity is very expensive, even if we summarize only household appliances, it becomes clear - home heating with cheap electricity can not be. To verify this fact, the calculation of energy consumption and the conversion of results into spent funds are described below.

How to determine the consumption of liquefied gas?

If you think about it, there is no particular difficulty here. The calorific value (calorific value) of the reduced gas (LNG) of the most common type (propane-butane mixture G30) is known. It is 42.5 MJ/kg. That is, burning a kilogram of LNG releases 42.5 megajoules of heat.

At the household level, we are probably more accustomed to measuring energy in other units, in watts and kilowatts. And it is more convenient to perceive a liquid substance in terms of volume, for example, in liters.It is not difficult to recalculate, knowing the density of LNG and the relationship of fundamental physical quantities - the energy potential of liquefied gas G30 is approximately 6.58 kW / dm³, in other words - per liter.

And how to find out the need of a particular house for thermal energy, so that in winter it maintains a comfortable temperature for all residents? Nothing is impossible either!

When calculating gas consumption, the efficiency of the boiler and some other nuances are also taken into account.

The whole calculation is embodied in the calculator below. If there are ambiguities, explanations to the program will help.

Calculation explanations

The user only needs to enter a few initial parameters on which the calculation is based:

The total heat demand of the building. Where to get this value - we have already said above

Important - it should not be confused with the nameplate capacity of the installed (planned to be installed) gas boiler. The calculated value is taken.
If the owners purchase a condensing boiler, then they take a very serious step in terms of saving gas consumption

The operation of this device is based on the additional selection of heat generated during the condensation of water vapor - one of the products of gas combustion. "Appendix" turns out to be very significant!
It must be found in the product passport and indicated in the appropriate field of the boiler efficiency calculator. Moreover, if two values ​​are indicated, then our calculator requires an efficiency factor for Hi (for the lower calorific value of gas).
Finally, you will need to clarify the price level with local LPG suppliers. Naturally, it is desirable immediately, taking into account the delivery. If there are several suppliers, then you can choose the best offer from your point of view.

It remains to press the button "CALCULATE ...", and get the finished result. Or rather, a whole “package” of calculated values.

— Average LNG consumption per hour, per day, per week, at maximum load, expressed both in liters and in kilograms.

— Approximate monthly consumption, also in liters and kilograms. Moreover, such consumption will be characteristic of the coldest month of the heating season. Immediately - recalculation in monetary terms.

- Finally, the total approximate consumption for the entire heating period is shown, based on its duration of 7 months. Also - with the display of the estimated costs for the purchase of gas.

For ease of perception, all types of expenses are also translated into the number of fully filled cylinders of a standard 50-liter capacity (taking into account the technology from filling - not "to the eyeballs"). Or maybe it’s better for someone - he does not regret investing in the construction of a gas tank, and intends to supply gas to the boiler room from a collector cabinet with several cylinders. This option can also be calculated in advance. True, it usually turns out to be more expensive in operating costs (but it wins in preparatory ones).

There is no way to mount a gas tank - you can limit yourself to cylinders in a manifold cabinet. Truth. there will be more trouble with such a scheme.

It will be interesting, for sure, to compare the result obtained with the hypothetical costs if it is possible to connect to the mains gas. It is possible that such a comparison will inspire someone to decide to still concentrate their efforts and finances on laying a gas pipeline to their home.

We try to make the best materials on the subject of construction and repair in Russia.To support professional content, be sure to write in the comments what do you think about heating with liquefied gas from a gas tank? How do you heat your house?

For example - a project of a one-story house of 100 m²

In order to clearly explain all the methods for determining the amount of thermal energy, we suggest taking as an example a one-story house with a total area of ​​​​100 squares (according to external measurement), shown in the drawing. We list the technical characteristics of the building:

• the region of construction is a temperate climate zone (Minsk, Moscow);
• thickness of external fences - 38 cm, material - silicate brick;
• external wall insulation - foam plastic 100 mm thick, density - 25 kg / m³;
• floors - concrete on the ground, no basement;
• ceiling - reinforced concrete slabs, insulated from the side of the cold attic with foam plastic 10 cm;
• windows - standard metal-plastic for 2 glasses, size - 1500 x 1570 mm (h);
• entrance door - metal 100 x 200 cm, insulated from the inside with extruded polystyrene foam 20 mm.

The cottage has half-brick (12 cm) interior partitions, the boiler room is located in a separate building. The areas of the rooms are indicated on the drawing, the height of the ceilings will be taken depending on the calculation method being explained - 2.8 or 3 m.

Calculation of gas flow from a gas tank

The calculation of the consumption for heating of the mixture from the gas storage used in the heat supply system of the house has its own characteristics and differs from the calculation of the consumption of the main natural gas.

The predicted volume of gas consumption is calculated by the formula:

V = Q / (q × η), where

V is the calculated volume of LPG, measured in m³/h;

Q is the calculated heat loss;

q - the smallest specific value of the heat of combustion of gas or its calorie content.For propane-butane, this value is 46 MJ/kg or 12.8 kW/kg;

η - efficiency of the gas supply system, expressed in absolute value to unity (efficiency / 100). Depending on the characteristics of the gas boiler, the efficiency can range from 86% for the simplest to 96% for high-tech condensing units. Accordingly, the value of η may be from 0.86 to 0.96.

Assume that the heating system is planned to be equipped with a modern condensing boiler with an efficiency of 96%.

Substituting in the original formula the values ​​\u200b\u200baccepted for calculation, we obtain the following averaged volume of gas consumed for heating:

V \u003d 9.6 / (12.8 × 0.96) \u003d 9.6 / 12.288 \u003d 0.78 kg / h.

Since a liter is considered to be a LPG filling unit, it is necessary to express the volume of propane-butane in this unit of measurement. To calculate the number of liters in the mass of a liquefied hydrocarbon mixture, kilograms must be divided by density.

The table shows the values ​​of the test density of liquefied gas (in t / m3), at various average daily air temperatures and in accordance with the ratio of propane to butane expressed as a percentage

The physics of the transition of LPG from liquid to vapor (working) state is as follows: propane boils at minus 40 ° C and above, butane - from 3 ° C with a minus sign. Accordingly, a 50/50 mixture will begin to pass into the gaseous phase at a temperature of minus 20 °C.

For mid-latitudes and a gas tank buried in the ground, such proportions are sufficient. But, in order to protect yourself from unnecessary troubles, it will be optimal in winter conditions to use a mixture with at least 70% propane content - “winter gas”.

Taking for the calculated density of LPG equal to 0.572 t / m3 - a mixture of propane / butane 70/30 at a temperature of -20 ° C), it is easy to calculate the gas consumption in liters: 0.78 / 0.572 \u003d 1.36 l / h.

Daily consumption with such a selection of gas in the house will be: 1.36 × 24 ≈ 32.6 liters, during the month - 32.6 × 30 = 978 liters. Since the obtained value is calculated for the coldest period, then, adjusted for weather conditions, it can be divided in half: 978/2 \u003d 489 liters, on average per month.

The duration of the heating season is calculated from the moment when the average temperature during the day outside does not exceed +8 degrees Celsius for 5 days. This period ends in spring, with stable warming.

In the area that we took as an example (Moscow region), such a period averages 214 days.

Gas consumption for heating during the year, when calculated, will be: 32.6 / 2 × 214 ≈ 3488 l.

Additional Factors Determining Pellet Consumption

The above calculation method is good only in theory, but in reality, the volume of real consumption of fuel pellets can significantly differ from these indicators up or down. In fact, the consumption of pellets for heating a house of 100 m2 depends on many factors, of which the most important are two:

• characteristics and efficiency of the solid fuel boiler used,
• operating mode of heating equipment.

Along with the quality of pellets, these factors have a significant impact on daily consumption and, in general, on the cost of heating. The owner of a private house can significantly reduce these costs by choosing high-tech and economical equipment and skillfully regulating its operation.

Consumption reduction

This is known: if the house is well insulated, then the fuel consumption for heating will be significantly reduced. Therefore, before starting the selection and installation of equipment and laying the main tracks, it is necessary to insulate the house well: walls, roof and attic, floor, replace windows, make an airtight sealing circuit on the doors.

Particular attention should be paid to the roof and windows. It is assumed that out of 100% of the lost heat, 35% escapes through the roof, about 25% is lost at the windows. Therefore, use the best thermal insulation materials and good double-glazed windows that have a low thermal conductivity.

Cheap double-glazed windows are immediately visible: their aluminum or steel “skeleton” is always very cold in winter, and a lot of heat is lost directly through it. Even the glasses themselves do not transmit heat as much as the metal profile on which these glasses are held does.

Therefore, use the best thermal insulation materials and good double-glazed windows that have a low thermal conductivity. Cheap double-glazed windows are immediately visible: their aluminum or steel “skeleton” is always very cold in winter, and a lot of heat is lost directly through it. Even the glasses themselves do not transmit heat as much as the metal profile on which these glasses are held does.

Advantages and disadvantages of using gas boilers in large areas

Gas heating has its benefits:

• When using this fuel, the walls of the boiler are not damaged by corrosion. This factor increases the life of the equipment.
• Gas is an ecological material. When it burns, no harmful substances enter the atmosphere.
• Due to the small amount of sulfur, a high efficiency of gas combustion is achieved.

The use of gas boilers is also beneficial:

Installing equipment is much cheaper than connecting to the highway;
Gas in cylinders has the best properties.
The operation of the boiler does not depend on pressure and breakdowns in the line.
Gas consumption for heating a house of 150 m2 in winter is significantly reduced.
Modern equipment is equipped with various security systems

This is important, because gas is a flammable and explosive substance. Disadvantages include:

The disadvantages include:

• the need for constant replacement of cylinders;
• dependence on atmospheric pressure;
• shutdown of system automation in case of power failure.

Important! Regardless of which system the boiler is powered by (autonomous or main), at the beginning of the heating season, check and adjust the settings. Repairs should only be carried out by a specialist

Do not forget about the mandatory ventilation of the room and compliance with safety regulations.

How to reduce gas costs

The calculated gas consumption for heating the house does not affect the costs associated with hot water supply or the use of a gas stove for cooking. In order for the real figure to be slightly more or even less, it is recommended to think about taking measures that will save money. Among the most common are:

• Roof insulation
• Wall insulation
• Replacing old windows with new ones

Roof insulation

One of the weak points in a private house is the roof. Hot air, rising up, will be replaced by colder masses from the attic space, if paths are “opened” to it there.

The easiest and cheapest way to prevent heat loss is to lay mineral insulation in the attic (sold in the form of rolls or plates). They easily fit between the rafters, do not require additional fixing or finishing.

You can read detailed instructions for roof insulation here.

Wall insulation

More than 45-50% of the heat leaves the house through cracks in the walls

That is why it is so important to insulate them well using any preferred thermal insulation material on the market.

The easiest way to insulate walls is to use ordinary foam or more modern varieties, such as extruded polystyrene foam. By attaching the boards to the wall, they can be easily and quickly sheathed with siding or plastered.

You can find a detailed guide to insulating walls from the outside in our last article.

Replacing old windows

Old windows are "open doors" for expensive heated air. Experts say that about 20-30% of heat flows through them, which is replaced by cold air currents.

It is possible to seal all the cracks before each heating season, but in this case you will have to face constant troubles. There will be savings, but it is very illusory compared to that achieved by installing new PVC models.

Other popular methods

It is worth paying attention to how modern gas heating equipment is installed. Newer and multifunctional boilers are characterized by greater efficiency

Additions such as a circulation pump, a temperature sensor will not be superfluous.

It is worth considering and building a hydraulic arrow, from which pipes will be laid to each heating device. By installing a temperature sensor and a programmable device in each room, the system will independently determine when and how much to warm up the controlled room.

Each battery is recommended to be equipped with a thermal head. So that the wall behind the heater does not absorb heat, you can fix a reflective foil screen on the surface. Furniture should not interfere with the free circulation of air around the radiators.

It is recommended to install an individual gas meter in the apartment. This will ensure that payment is made only for the actual amount of energy consumed.

Summing up

Of course, having calculated the gas consumption for heating a house and comparing the cash costs with other types of energy carriers, one can note an obvious economic benefit. However, in practice, the numbers may be slightly different, as they will be influenced by third-party factors.

How to reduce gas consumption

A well-known rule: the better the house is insulated, the less fuel is spent on heating the street. Therefore, before starting the installation of the heating system, it is necessary to perform high-quality thermal insulation of the house - the roof / attic, floors, walls, replacing windows, hermetic sealing contour on the doors.

You can also save fuel by using the heating system itself. Using warm floors instead of radiators, you will get more efficient heating: since heat is distributed by convection currents from the bottom up, the lower the heater is located, the better.

In addition, the normative temperature of floors is 50 degrees, and radiators - an average of 90. Obviously, floors are more economical.

Finally, you can save gas by adjusting the heating over time. It makes no sense to actively heat the house when it is empty. It is enough to withstand a low positive temperature so that the pipes do not freeze.

Modern boiler automation (types of automation for gas heating boilers) allows remote control: you can give a command to change the mode through a mobile provider before returning home (what are Gsm modules for heating boilers). At night, the comfortable temperature is slightly lower than during the day, and so on.

Issue price

In the Chelyabinsk Region, the cost of 1 cubic meter of natural main gas is 6.15 rubles/m3.

Liquefied mixture in cylinders, without delivery, depending on the region, is 16.82 - 19.26 rubles per kilogram.

The amount of fuel for heating an individual house is reduced by any of the three measures, or by the whole complex:

1. 1. A simple event - installation of a thermal curtain in the entrance block. Such models do double duty. In winter, the device cuts off cold air from the street, in summer the unit is turned on for cooling, at the same time preventing the appearance of insects in the rooms. Thermal curtains are equipped with overheating protection and a remote control.
2. Expensive, but not difficult to perform - underfloor heating, which requires heating water at half the temperature of radiator heating. Water floors are inexpensive, and they have a plus: they heat, but do not overdry the air. However, remember that water floors, according to the rules, are installed only in a private house. In apartment buildings, the option of a cable or film floor is being considered.
3. Even in a 100 sq. m will justify the installation of automatic regulation of heat supply depending on the outside temperature and the presence of people in the house.