During the modernization of the hot water heating system, the wood burning stove was replaced with a natural gas stove. The specific heat of combustion of firewood is 10 7 J / kg, natural gas - 3.2 10 7 J / kg. How is it necessary to change (increase or decrease) the mass of fuel burned in the furnace per unit time in order to maintain the same rate of water circulation in the heating system? Explain the answer.

Water heating

The need for heating arose in ancient times, at the same time as people learned to build the most primitive dwellings for themselves. The first dwellings were heated by bonfires, then they were replaced by hearths, then by stoves. In the course of technological progress, heating systems have been constantly improved and improved. People learned to use new types of fuel, invented different designs heating appliances, sought to reduce fuel consumption and do the job heating system autonomous, not requiring constant human control. At present, water heating systems are most widely used, which are used to heat both apartment buildings in cities and small buildings in countryside. The principle of operation of a water heating system (see figure) is conveniently explained using the heating system of a small residential building as an example.

The source of heat for the heating system is furnace 1, in which different kinds organic fuel - firewood, peat, coal, natural gas, oil products, etc. The furnace heats the water in the boiler 2. When heated, the water expands and its density decreases, as a result of which it rises from the boiler up the vertical main riser 3. In the upper part the main riser is located with an exit to the atmosphere expansion tank 4, which is necessary due to the fact that the volume of water increases when heated. Pipe 5 departs from the upper part of the main riser (“hot pipeline”), through which water is supplied to heating devices - batteries 6, each consisting of several sections. After flowing through the batteries, the cooled water through the return pipeline 7 again enters the boiler, heats up again and rises again through the main riser. With the simplest one-pipe scheme, all batteries are connected to each other in such a way that all sections are connected in parallel to the hot and return pipelines. Since the water gradually cools as it flows through the batteries, in order to maintain the same temperature in different rooms they make batteries with a different number of sections (that is, with different area surfaces). In those rooms in which water enters earlier and therefore has a higher temperature, the number of sections in the batteries is reduced, and vice versa. The water in such a heating system circulates automatically as long as the fuel is burning in the furnace. In order for circulation to be possible, all hot pipelines and return pipelines in the system are made either vertical or with a slight slope in the right direction - so that water flows through them from the main riser back to the boiler under the action of gravity ("gravity"). The rate of water circulation and the degree of heating can be adjusted by reducing or increasing the amount of fuel burned in the furnace per unit time. Water circulates in heating systems of this type the better, the greater the distance in height between the boiler and the hot pipeline. Therefore, they try to place the stove with the boiler as low as possible - usually they are placed in the basement or, in its absence, lowered to ground level, and the hot pipeline is carried through the attic.

For normal operation of the heating system, it is very important that there is no air inside it. To release air locks that may occur in pipes and batteries, special air vents are used, which open when the system is filled with water (not shown in the figure). Also, taps 8 are installed on the pipes in the lower part of the system, with the help of which water is drained from the heating system, if necessary.

Solution.

Answer: reduce.

Explanation: the rate of water circulation in the heating system, other things being equal, is determined by the rate of water heating in the boiler. When burning natural gas, more heat is released than when the same mass of firewood is burned, and the water in the boiler heats up faster. Therefore, in order to maintain the same rate of water circulation in the system, it is necessary to reduce the mass of fuel burned in the furnace.

The owner of a suburban residential building with an area of ​​more than 500 sq.m applied with a problem of operating the heating system. The difficulty of the owner was the inability to control the temperature in the premises, which led to discomfort for all family members.

The situation in which the owner found himself can be compared to the operation of an expensive luxury car, in which there is a stove, but there is no temperature regulator, not to mention climate control.

The only adjustment method found was a screwdriver, with which the valve connected from below to the radiator was covered. And, of course, so manually increasing and decreasing power, the desired temperature in the room was still never achieved.

Danfoss engineers, having studied the wishes of the owner, proposed an automatic temperature control solution using RET2000B wireless room thermostats and recommended a certified installation company for site visit and subsequent installation.

According to the results of the site survey, it turned out that during the installation of the heating system of the house, no zonal control of radiators and convectors in the floor was provided. At the same time, when laying pipelines, it was applied collector system. In total, there are 5 cabinets in the house with distribution manifolds of the system radiator heating.

Installation thermostatic elements on radiators was not possible due to the fact that they were hidden by screens, and their installation would lead to an incorrect operation mode. And given the fact that the house carried out a high-quality repair using expensive materials, the only possible solution began the installation of wireless room thermostats in all rooms where it was necessary to regulate the temperature. the only extra work The task that had to be carried out was the power supply to each cabinet for connecting the switching device and the signal receivers from the room thermostats.

Installation of equipment for automating the heating system took no more than 5 hours and took place in the following sequence:

1. Determine the heating circuit and the heater connected to it;
2. Install electric actuators on the valves of the distribution manifold of the corresponding circuits, which open or close the valve on a signal.
3. Install the terminal panel in the collector cabinet and connect the signal receivers and electric drives.
4. Connect room thermostats and receivers;
5. Mount the thermostat on the wall of the room at a height of 1.5 meters from the floor and set the required temperature.

Since the project is internal engineering systems was absent, the specialists were forced to empirically track all the lines from the manifold cabinet to heater. It turned out that in the big room not all 12 radiators were connected to the same distribution manifold. But here, too, a solution was quickly found. One room thermostat connected with two wireless signal receivers located in different cabinets, but at the same time regulating the temperature of appliances in the same room.

The principle of operation of room thermostats is very simple: as soon as the temperature set on the thermostat is reached in the room, for example 21 ° C, the thermostat accordingly sends a signal to the receiver installed in the cabinet. And the receiver, in turn, gives a command to the electric drives connected to it to close the valve. Thus, the supply of coolant to the corresponding heating circuits is stopped, and the heat output of the radiators does not increase until the room thermostat detects a decrease in the temperature in the room.

Danfoss engineers and partners often have to deal with cases where the automation of the heating system has not been thought through during the installation of the heating system. The reason may be both the desire to save on the heating system, and the lack of the necessary qualifications from the engineers of the installation organization.

Unconditional advantage wireless solutions from Danfoss is the ability to upgrade almost any radiator heating system and water heated floor system.

Teploraschet-proekt and PSK Prometey provide services for calculation, design, installation, reconstruction and modernization of heating and heat supply systems. Specialists carry out gasification of facilities, including project preparation, installation, commissioning works and service.

Modernization of heating systems is a set of measures to replace obsolete or worn-out equipment of autonomous and district heating systems.

The modernized heat supply system meets the following requirements:

• Environmental friendliness. 20-40% less emissions produced harmful substances(CO2, CO, NOx, SO2, PbO2).
• Energy efficiency. The efficiency is above 80-90%.
• Profitability. Energy consumption in the system is reduced to 30-40%.

Depending on the condition of the existing equipment, these indicators are achieved both through partial replacement individual parts and assemblies, and due to the complete modernization of heating systems.

Modernization of heating sources

In the process of modernization of heating sources (boilers and CHPPs), the following works are performed:

• design of gas boilers or other sources of heat energy production;
• the cost of gasification is calculated;
• gasification of an enterprise, microdistrict, multifunctional building or house;
• routine adjustment or replacement of chemical water treatment equipment;
• replacement of the heat generator and operating units (steam generator, burner, pump, heating boiler);
• automation of heating systems and load control.

Modernization of heating networks

In heat networks (supply and return pipes that transport heat energy from a heating source to a consumption point), heating systems are upgraded in several stages:

1. A detailed survey is carried out on all sections of the network from the heat source to the entrance to the building. It is carried out to identify problems and their causes.

2. Thermal and hydraulic calculations in several variants. Based on the data obtained, network diagrams are drawn up and equipment is selected that performs adjustment (chokes, balancing valves, automatic systems regulation).

3. Designed heating network and a way to control the load based on the most economical and efficient option.

4. Commissioning activities are being developed and carried out.

Modernization of heat consumption systems

The heat consumption system (radiators, convectors, gas fan heaters, heaters and other equipment that transmits thermal energy to the consumer) is brought into line with the characteristics of the heating network and the heating source in terms of thermal and hydraulic indicators. Modernization of heating systems is provided if the following units are installed:

• Supply air volume control devices. Are established in addition on units of heating and ventilation. They allow to take into account the need for heated air and control the amount of heat supplied to the room depending on the time of year and day;
• Nodes of mixing and regulation of water temperature. Are established in addition on units of heating and ventilation. The temperature is maintained by supplying cooled water from the return pipeline to the radiator;
• Gas infrared heating. It is installed as an alternative or in addition to water and air heating systems. Gasification of a cottage, apartment building or commercial facility using this equipment involves the location of heaters under the ceiling to direct heat radiation to all surfaces in the room.

The above units are equipped with automatic control systems for effective management of the thermal regime of heated premises.

In order to modernize the heat supply system, determine the list of works, calculate the cost or prepare a gasification project, you can call the specialists of Teploraschet-Proekt LLC and PSK Prometey LLC at the numbers posted in the Contacts section.

Hello dear Reader!

I want to tell you about what heating systems I had to deal with.

Some he exploited, some he assembled himself, including heating systems for private houses.

I learned a lot about their pros and cons, although, probably, not everything. As a result, for my house I did:

• first, own scheme;
• secondly, it is quite reliable;
• thirdly, allowing modernization.

I suggest not to delve into the detailed study various schemes heating.

Let's look at them from the point of view of application in a private house.

After all, a private house can be for permanent residence, and temporary, like a dacha, for example.

So to speak, let's narrow our topic and get closer to practice.

About ten years, maybe I was wrong. I started servicing the first heating system 33 years ago, when I was a student at the Ural Polytechnic Institute. I was lucky to get a job in the institute's boiler room as a mechanic on duty. True, at that time I didn’t even think about what kind of system it was? Worked and everything.

The work was sometimes difficult when there was an accident. And if everything is fine - beauty, sit yourself and learn notes. Night on duty, in the morning to study, "to school", as we then said. Back on duty two nights later. And most importantly, they paid 110 - 120 rubles! At that time, young professionals received the same amount. Yes, plus a scholarship of 40 rubles. Posh life! But, let's get closer to the heat.

From the name itself it is clear that heating occurs with heated air. The air is heated by a heat generator, and then it enters the premises through ducts. The cooled air is returned through the return channels for heating. Pretty comfortable system.

The first heat generator in history was a furnace. She heated the air, which diverged through the channels in the order of natural circulation. Such an air heating system was used in the past centuries in advanced city houses.

Now they use a variety of heat generators-boilers: gas, solid fuel, diesel, electric. In addition to natural circulation, forced circulation is also used. It is, of course, more efficient:

• Firstly, it warms up the premises much faster;
• Secondly, it has a higher efficiency, since heat is removed from the heat generator much more efficiently;
• Thirdly, it can be combined with the air conditioning system.

You probably already understood that here it doesn’t “smell” like a private house. Yes, that's right, for a private house this heating scheme is too cumbersome and expensive. Some calculations are worth something, and if you make a mistake, then it will be, as they say, fatal.

But let's not get upset. If you still want to be heated by air, there is a way out. This is a fireplace.

Moreover, in my opinion, not an ordinary firewood-eater fireplace, but a cast-iron fireplace insert shown in the figure above. it perfect option home cozy wood-fired heat generator. It is designed specifically for heating air, and not bricks, like a traditional fireplace.

The air enters the space under the fireplace (where the firewood lies for the entourage), flows around its heated body. Then it flows around the red-hot chimney along the fireplace box and exits through the holes in the upper part of the box. By the way, air ducts can be connected to these holes and hot air can be distributed throughout the premises.

Quite a worthy option, only if done with air ducts, then during construction you need to remember to put them in walls and ceilings. Someone also puts a blower, creating forced ventilation. But this, in my opinion, is overkill. By the fireplace, it is nice to hear the crackling of firewood, rather than the noise of a fan.

I think it is worth mentioning more fan heaters and heat guns. These are, so to speak, mobile air heating units. Highly useful appliances, especially when the main heating system is not working or you need to quickly “warm up” the air in the room. But, in my opinion, they cannot be considered as the main heating option.

So, a fireplace insert, as a source of air heating, is a good, and, moreover, a pleasant solution for a private house.

Water heating at home

In this case, the coolant is water or special liquids, for example, non-freezing. Here, the heat sources are also very different depending on the fuel. But if in air system warm air comes into the room, then into the water air of the room heated by appliances who give him heat stored in water.

And the water stores a lot of heat. There is such a thing: "heat capacity", remember? If in your own words

The heat capacity of water is the amount of heat that must be transferred to water in order for its temperature to rise by one degree.

So this indicator near the water is very good. Look at the table on the right.

It turns out that we get a chic coolant almost for nothing.

Yes, water system somewhat more complex, but also more flexible.

Imagine that heated water can be supplied through pipes anywhere and there it will give off the accumulated heat.

And the pipes can be easily hidden in the walls, or you can not hide them at all, modern ones look very aesthetically pleasing.

How does water give off heat? For this, several types of devices have been created:

• Radiators - massive, for example cast iron, sections assembled into batteries.

Inside them flows hot water. thermal energy they give, mainly at the expense of infrared radiation(radiation).

They are usually steel or aluminum, less often copper. The surrounding air, being heated by the convector, begins its natural upward movement. That is, a flow (convection) of air is created, which removes heat from the convector.

Modern aluminum appliances also belong to convectors, although they are called radiators. It should be noted that now almost all thermal devices for water heating are called radiators, although strictly speaking, this is wrong. But let's not be smart.

Air is pumped through them to be heated. Commonly used in systems supply ventilation to heat the cold air coming in from outside.

• "Warm walls" - were used in the seventies in panel housing construction. A serpentine from steel pipe, into which water was supplied from the heating system. I remember from childhood warm walls panel five-story buildings.

The water system can be successfully used in a private house. If this is a dacha, you can fill in a non-freezing coolant instead of water and not worry about defrosting the system.

Let's take a closer look at the options for heating systems for low-rise buildings.

Scheme of a gravity heating system

Why self-flowing? Because the water in it actually flows by itself. When heated in the boiler, the water rises, and then, gradually cooling in the radiators, flows down and returns to the boiler again. The system is simple, but the prerequisites must be observed:

• The pipe should be pretty large diameter from 50 mm, and preferably 76 mm and more.
• The pipe is laid with a slope to ensure the gravity flow of water.

Sometimes this very pipe heats the room without radiators and convectors due to its large mass and surfaces. Such pipes are called registers, they can be found at railway stations and bus stations of old small towns. It is now rarely used in private homes - it does not look very aesthetically pleasing. Imagine - there is a thick pipe in the room, and even an inclined one.

A very big advantage of this system is that it does not need a circulation pump, the water circulates itself. If the boiler is wood, coal or gas - no power outages are terrible, complete autonomy and independence. I'm talking about this because I myself have trouble with power outages.

A feature of a gravity-flow system, which is considered a disadvantage, is that it is open, that is, it communicates with air and there is no pressure in it. This means that an open expansion tank is needed and the water gradually evaporates, you need to monitor this. Of course, this is not a very serious drawback. I'm more repulsed by high sloping pipes.

For a private house closed system heating I think best option. It's better to say closed. Closed means not in contact with air. Here are the new elements:

• Membrane expansion tank to compensate for the expansion of water when heated;
• Circulation pump for pumping water through the system;
• Safety group - make-up valve (for adding water to the system in case of leakage), pressure gauge, safety valve (for releasing steam when water boils).

This is a more modern, aesthetic option. Radiators are used here, and more often aluminum convectors, thin metal-plastic or polypropylene pipes. There is no need to add water, think about the slope of the pipes, they can generally be hidden in walls or ceilings.

You can put beautiful aluminum or bimetal radiators, heated towel rail. I use two boilers in one system - an electric boiler and a water circuit for a fireplace insert. Like it worked out well.

Minus the system - without electricity for circulation pump she can't work. Moreover, if the firebox is “under steam” and the electricity is over, it can turn out to be a “boomsik” with the release of steam and a lot of noise. I know for myself. It looks like the pipes are being pounded with a hammer.

Therefore, the pump was connected to an uninterruptible source (like a computer) so that there was time to safely cool the firebox. And another way out safety valve- into the sewer.

Two-pipe heating system

There are two options for connecting radiators to the heating system:

The only plus single pipe system- Savings on pipes. But the minus is significant - the radiator closest to the boiler is the hottest, and the farthest is the coldest. And it’s also problematic to turn off some kind of radiator - they are all in the same circuit. If this is not critical, why not use this option? It's a perfectly normal pattern.

The two-pipe scheme is more flexible:

• All radiators are almost equal. Water is supplied to each at the same temperature;
• You can set your own temperature on each radiator by regulating the flow of water through it;
• You can painlessly shut off the water supply to any radiator, for example, when it's hot or you need to flush the radiator;
• More convenient for increasing the number of radiators.

Thus, in my opinion, a two-pipe scheme is more preferable.

For the sake of justice, it must be said that in the two-pipe version, the last radiator is somewhat “offended”, it gets less heat. The reason is that on it the pressure difference between supply and return is almost zero and the water flow is minimal.

So what choice did I make?

I installed an air-to-water heating system in my house. The fireplace is responsible for the air. Closed two-pipe water circuit includes an electric boiler, a water circuit for a fireplace insert and 40 aluminum radiator sections (6 radiators). 64 square meters the first floor in any frost are heated in excess.

That's all for today. In the following articles I will bring to your attention the system gas heating, underfloor heating, infrared heating. Comment, ask questions. Thanks, see you!

A country house is the dream of every city dweller. This type of real estate has a lot of advantages over an apartment, ranging from the lack of noisy neighbors and ending with the picturesque surrounding landscapes. But one of the fundamental advantages of living outside the city is still the ability to choose and implement the most productive and inexpensive heating system.

The most common and popular heating scheme for a private cottage today is water heating with a lower wiring. Of course, since its inception a hundred years ago, it has undergone significant changes and modernization, acquired several modifications, and therefore there is plenty to choose from. Moreover, of all the existing schemes, it is the water scheme that is distinguished by the most optimal combination of “price-efficiency” parameters.

Home water heating systems: heat generators, features

The basis of the water heating scheme of a private house is a fuel unit - a boiler. As a rule, the choice of one or another type of heat generators is selected depending on the mass of parameters, including the personal preferences of property owners, the characteristics of the region and the availability of one or another type of fuel.

Often, all kinds of solid and liquid fuel units, gas or electrical devices. It should be noted that the most popular in our country are solid fuel and gas boilers, since fuel for them has the most affordable cost and, importantly, it is affordable - it is common in all regions.

In addition to the boiler itself, other elements are also used in the water heating of the house. So, for example, if the house has stove heating, then a variety of coils, registers and hollow built-in elements will help to upgrade it to water. In this case, the resulting circuit can already be called a combined one, distinguished by its simplicity and increased efficiency.

There is no fundamental difference in the procedure for installing the heating system, depending on the type of boiler. Simply follow the manufacturer's instructions.

In addition, due to the fact that water heating in a private house has a fairly versatile design, it is possible to install two or even three heat generators in parallel - this will achieve maximum performance, make the circuit completely autonomous, eliminate even the slightest risk of being left without heat in the cold room. winter time.

Advice. With such a parallel connection of boilers, it is important to consider the installation special system automation, which will help to ensure switching between units when the supply of one of the fuel types stops.

Water heating and natural circulation of the coolant

The most simple and affordable option water heating of a private house, which can be done without any problems and costs with your own hands. It cannot be said that the instruction for such a system does not imply any complex work for design and installation, implies the use of only available materials and accessories.

If we talk about the principle of operation, then for water heating with natural circulation of the coolant, it is extremely simple. The water heated in the boiler rises up the pipeline (due to the difference in temperature differences), gradually entering all the radiators located around the house, while the cooled water returns to the heat generator again. Provided without the use of additional equipment.

Advice. When using a scheme with natural circulation of the coolant, it is important to ensure that the main pipelines are laid with a certain slope.
Often, 3-5 degrees per 1 running meter(about 10 mm).
Otherwise, the system will work, but the efficiency will be significantly reduced, which will lead to extra costs fuel.

The wiring can be done metal pipes different diameter- the choice depends on the characteristics of the boiler and radiators. A prerequisite one can also name a decrease in the cross-section of pipes towards the most extreme point of the heating circuit - the last radiator.

The pipe through which the water heated in the boiler is supplied to the system must be installed in such a way that its slope towards the radiators is maximum. The return point to the heat generator is made as low as possible in relation to the batteries - this is done for fast and efficient circulation of the coolant. This can be done by installing a thermal unit in the basement or basement.

Another integral attribute of a natural circulation water heating scheme is an expansion tank. Unlike a boiler, a similar unit is installed at the highest point of the cottage, the best option is the attic. It is possible to use hydroaccumulating tanks, but in this case it is important to ensure the installation of additional equipment, such as pressure gauges, air and safety valves.

Advice. Since in many houses the attic is not heated during the cold season, it is important to take care of the insulation of the expansion tank.
In this case, you can use heaters of the most various types, their choice in our time is extremely wide. The main requirement is impact resistance. high temperatures(up to 90C).

In addition to distributing water heating at home, plastic ones can also be used. Such pipes are easy to install, therefore, time installation work will be less.

Forced circulation in water heating systems

Another option for arranging heating country cottage- a scheme of water heating in a private house with forced circulation of the coolant. Main distinguishing feature- the presence of a special circulation pump.

The device allows you to achieve more efficient and high-quality pumping of water in the system, to ensure its supply even to the highest points of the house without loss of heat (especially good for cottages with two or three floors).

Unlike schemes with natural circulation, heating with forced movement of the coolant is not too demanding on the slope of the pipes. Yes and efficiency similar systems almost 20-30% higher than those where water moves along highways through natural circulation.

With the forced movement of the coolant, hydroaccumulating tanks are used instead of traditional ones. Since the pressure in pipes and radiators can increase up to 1.5-2 atm, it is important to provide for the installation of special safety devices: safety and air valves, pressure gauges, etc.

On both sides of the circulation pump should be located shut-off valves, due to which it is possible to ensure the shutdown of the coolant supply to the system.

The main types of water heating wiring

To date, there are several main options for piping around the house when using water heating:

• Single pipe. The so-called "Leningrad", in which one pipe connects all the heaters in the house in the direction of the coolant. Such a scheme is chosen for simplicity, minimal financial (the price of highways is generally lower) and labor costs.

But at the same time, the heating of the radiators is uneven, and it is impossible to regulate the temperature in each of the batteries;

• Two-pipe. The connection of heating radiators is made by two pipes laid parallel to the movement of water in the system.
  The advantages include the ability to quickly adjust the temperature, quick and uniform heating of the premises, accessibility;
• Collector arrangement of pipes. It has its own supply and return pipeline, connected together with the help of special distribution manifolds.
  Feature - beautiful appearance, full control over all the batteries in the house from the switch cabinet.

The main advantages of water heating of the cottage

As you can see in the photo and video country houses on our website, water heating schemes are used quite often in our country.

There are many reasons for this widespread use:

1. The ability to perform installation work on the arrangement of home heating at any stage of construction. Moreover, even in finished house water heating is installed without any problems;

1. Water itself has excellent qualities when used as a heat transfer medium. High thermal conductivity, availability and low cost, along with unique heat capacity, make water the best choice;
2. Versatility, the ability to use different types of fuel to heat the coolant in the heating circuit;
3. Large selection of piping options in water heating schemes. You can choose a certain type depending on the mass of parameters, ranging from the area of ​​\u200b\u200bthe cottage and ending with financial capabilities;
4. A variety of equipment for arranging home heating;
   
5. Accurate and quick adjustment of the air temperature in each of the rooms of a private house. It is provided by the installation of special equipment, namely temperature controllers and shut-off valves.

Conclusion

Today, there is simply no more affordable or effective alternative to water heating of a private house. It should be noted that every year more and more new heat generators, pipelines and radiators appear, due to which the efficiency of the scheme increases, while its cost decreases almost several times compared to other options.