Two DHW schemes for a country private house - which one to choose?
What needs to be done to ensure that hot water flows immediately after opening the tap?
Depending on the method of heating water hot water supply systems (DHW) for private country house divided into:
- DHW with instantaneous water heater.
- DHW with storage water heater (boiler).
Hot water supply diagram with instantaneous water heater
The following can be used as an instantaneous water heater:
- DHW gas water heater;
- DHW heating circuit of a double-circuit heating boiler;
- electric instantaneous water heater.
- plate heat exchanger connected to the heating circuit.
Instantaneous water heater begins to heat the water at the moment the water is drawn when the hot water tap is opened.
All energy spent on heating passes from the heater to the water almost instantly, for very a short time movement of water through the heater. In order to obtain water at the required temperature in a short period of time, the design of an instantaneous water heater provides for limiting the speed of water flow. The water temperature at the outlet of the flow-through heater depends very much on the water flow — the size of the stream of hot water flowing from the tap.
For normal supply hot water only one horn in the shower, the power of the instantaneous water heater should be at least 10 kW. You can fill a bathroom in a reasonable time using a heater with a power of more than 18 kW. And if, when filling the bathtub or running the shower, you also open the hot water tap in the kitchen, then For comfortable use of hot water, you will need a flow heater power of at least 28 kW.
To heat an economy class home, a lower power boiler is usually sufficient. That's why, power double-circuit boiler choose based on the need for hot water.
A DHW circuit with an instantaneous water heater cannot provide comfortable and economical use of hot water in the house for the following reasons:
- With low hot water consumption instantaneous water heater Doesn't turn on at all and doesn't heat the water. To obtain water at the required temperature, it is often necessary to spend more water than is necessary.
- Each time the water tap is opened, the instantaneous water heater starts again. It constantly turns on and off, which reduces the resource of its work. Each time, hot water appears with a delay, only after the heating mode has stabilized. Frequent restart of the heater reduces efficiency and increases energy consumption. Some of the water goes down the drain uselessly.
- It is impossible to recirculate water in the distribution pipes throughout the house. Hot water from the tap appears with some delay. The waiting time increases as the length of the pipes from the water heater to the water collection point increases. Some of the water at the very beginning has to be drained uselessly into the sewer. Moreover, this is water that has already been heated, but has managed to cool down in the pipes.
- Scale deposits accumulate quickly on a small surface inside the heating chamber of an instantaneous water heater. Hard water will require frequent descaling.
The temperature and pressure of water in the pipes very much depend on the amount of water flow. For this reason When you open another tap, the water temperature and pressure in the hot water system changes greatly. It is very uncomfortable to use water even in two places at the same time.
Ultimately, the use of an instantaneous water heater in a hot water supply system leads to an unreasonable increase in water consumption and volume of sewage waste, to an increase in energy consumption for heating, as well as to insufficiently comfortable use of hot water in the house.
A hot water supply system with an instantaneous water heater is used, despite its disadvantages, for the reason relatively low cost and small size equipment.
The system works better if Install a separate individual instantaneous water heater near each water collection point.
In this case, it is convenient to install electric flow heaters. However, such heaters, when drawing water simultaneously in several places, can consume significant power from the electrical network (up to 20 - 30 kW). Typically, the electrical network of a private home is not designed for this, and the cost of electricity is high.
How to choose an instantaneous water heater
The main parameter for choosing an instantaneous water heater is the amount of water flow that it can heat.
- from the tap of a sink or washbasin 4.2 l/min (0,07 l/sec);
- from the bath or shower tap 9 l/min (0,15 l/sec).
For example.
Three points of disassembly are connected to one instantaneous water heater - a sink in the kitchen, a washbasin and a bathtub (shower). To fill only the bathtub, you must select a heater that is capable of delivering at least 9 l/min. water with a temperature of 55 o C. Such a water heater will also provide the use of hot water simultaneously from two taps - in the sink and washbasin.
It will be comfortable to use hot water in the shower and washbasin at the same time if the heater capacity is no less than 9 l/min+4,2 l/min=13,2 l/min.
Manufacturers in technical specifications usually indicate maximum performance instantaneous water heater, based on water heating to a certain temperature difference, dT, for example 25 o C, 35 o C or 45 o C. This means that if the water temperature in the water supply is +10 o C, then at maximum performance water will flow from the tap with a temperature of +35 o C, 45 o C or +55 o C.
Be careful. Some sellers in advertising indicate the maximum performance of the device, but “forget” to write for what temperature difference it is defined. You can buy a gas water heater with a capacity of 10 l/min., but it turns out that at such a flow rate it will heat the water by only 25 o C., i.e. up to 35 o C. Using hot water with such a column may not be very comfortable.
Suitable for our example geyser or a double-circuit boiler with a maximum output of at least 13.2 l/min at d T=45 o C. The power of the gas appliance with these hot water parameters will be about 32 kW.
When choosing an instantaneous water heater, pay attention to one more parameter - minimum productivity, consumption l/min, at which the heating is turned on.
If the water flow in the pipe is less than the value specified in the technical characteristics of the device, the water heater will not turn on. For this reason, often you have to use more water than necessary. Try to choose a device with the lowest possible minimum performance, for example, no more than 1.1 l/min.
Electric instantaneous water heaters intended for domestic use have a maximum heater power of about 5.5 - 6.5 kW. At maximum performance 3.1 - 3.7 l/min heat water at d T=25 o C. One such water heater is installed to serve one water point - a shower, washbasin or sink.
DHW circuit with storage heater (boiler) and water circulation
The storage water heater (boiler) is a thermally insulated metal tank quite large volume.
Two heaters are most often built into the lower part of the water heater tank at once - an electric heating element and a tubular heat exchanger connected to the heating boiler (). The water in the tank is heated by the boiler most of the time.
Electric heater turns on as needed during the boiler shutdown period. This boiler is often called boiler indirect heating.
Hot water in an indirect heating boiler is consumed from the top of the tank. In its place, cold water from the water supply immediately enters the lower part of the tank, is heated by a heat exchanger and rises upward.
In EU countries DHW systems in new houses in mandatory equipped with a solar heater - collector. To connect solar collector another heat exchanger is installed in the lower part of the indirect heating boiler.
DHW diagram with layer-by-layer heating boiler
IN Lately The hot water supply system with a layer-by-layer heating boiler is gaining popularity, the water in which is heated by a flow-through water heater. This boiler does not have a heat exchanger, which reduces its cost.
Hot water is drawn from the top of the tank. In its place, cold water from the water supply immediately flows into the lower part of the tank. The pump drives water from the tank through a flow-through heater and supplies it directly to top part tank. Thereby, The consumer gets hot water very quickly— you don’t need to wait until almost the entire volume of water warms up, as happens in an indirect heating boiler.
Rapid heating of the top layer of water, allows you to install a smaller boiler in the house, as well as reduce the power of the flow-through heater, without sacrificing comfort.
The Galmet SG (S) Fusion 100 L layer-by-layer heating boiler is connected to the DHW circuit of a double-circuit boiler or to a gas water heater. The boiler has a built-in three-speed circulation pump. Boiler height 90 cm, diameter 60 cm. Manufacturers produce double-circuit boilers with built-in or remote layer-by-layer heating boiler. As a result,the cost and dimensions of the DHW system equipment are somewhat smaller,than with an indirect heating boiler.
The water in the boiler is heated in advance, regardless of whether it is spent or not. The hot water reserve in the tank allows you to use hot water in the house for several hours.
Thanks to this, heating the water in the tank can be done quite long time, gradually accumulating thermal energy in hot water. Hence another name for the boiler - cumulative water heater.
Long duration of water heating allows use a relatively low power heater.
Storage gas water heater - boiler
Storage boilers, the water in which is heated by a gas burner, are less popular in systems DHW private Houses. Installation of heating and hot water systems in the house with two gas appliances - a gas boiler and a gas boiler, it turns out noticeably more expensive.
Cumulative gas water heater- boiler It can be advantageous to install gas boilers in apartments with central heating or in private houses with heating solid fuel boiler and heating water in the hot water supply system with liquefied gas.
Gas water heaters, like boilers, are produced with open camera combustion and closed, with forced removal flue gases and with natural draft in the chimney.
Savings are available for sale gas boilers, which do not require connection to the chimney. (Household gas stoves They also work without a chimney.) The power of the gas burners of such devices is small.
Gas boilers with a capacity of up to 100 liters are designed for wall mounting. Large volume water heaters are installed on the floor.
Water heaters are used different ways gas ignition— with a duty wick, electronic on batteries or hydrodynamic ignition.
In the devices with a duty wick A small flame is constantly burning, which is first ignited manually. A certain amount of gas burns uselessly in this torch.
Electronic ignition works from the mains or battery, accumulator.
Hydrodynamic ignition it is launched by the rotation of a turbine, which is driven by the flow of water when the tap is opened.
How to choose the volume of a storage water heater - boiler
The larger the volume storage water heater- the higher the comfort of using hot water in the house. But on the other hand, the larger the boiler, the more expensive it is, the higher the costs for its repair and Maintenance, the more space it takes up.
The size of the boiler is selected based on the following considerations.
Increased comfort will be provided by a boiler, the volume of which is selected at the rate of 30 - 60 liters per user of water.
A high level of comfort will be provided by a water heater with a volume of 60-100 liters per person living in the house.
Almost all the water must be used to fill the bathtub. from a boiler with a volume of 80 - 100 liters.
How to choose boiler power for a DHW boiler
When choosing a boiler, you need to pay attention to the power of the heating element that is installed in it. For example, to heat 100 liters of water to a temperature of 55 o C within 15 minutes, a heater must be installed in the boiler (heat exchanger for the boiler, built-in gas-burner or heating element) with a power of about 20 kW.
In real operating conditions, the temperature of the water in the boiler is equal to the temperature of the water in the water supply only when the heating is first turned on. In the future, the boiler almost always contains water that has already been heated to a certain temperature. To heat water to the required temperature in an acceptable time, heating devices of lower power are used.
But it’s still better to check how long it will take to heat the water in the boiler. This can be done using the formula:
t = m cw (t2 – t1)/Q, wherein:
t– water heating time, seconds ( With);
m– mass of water in the boiler, kg (mass of water in kilograms equals the volume of the boiler in liters);
cw – specific heat water equal to 4.2 kJ/(kg K);
t2– the temperature to which the water should be heated;
t1– initial water temperature in the boiler;
Q– boiler power, kW.
Example:
Time for heating water with a boiler with a power of 15 kW in a 200-liter boiler from a temperature of 10 °C(we assume that the water entering the boiler has this temperature) up to 50 °C will be:
200 x 4.2 x (50 – 10)/15 = 2240 With, that is, about 37 minutes.
DHW scheme with water recirculation in the system
The use of a storage water heater in a domestic hot water system allows for the recirculation of hot water in pipelines. All hot water collection points are connected to a ring pipeline through which hot water constantly circulates.
The length of the pipe section from each point of hot water consumption to the ring pipeline should not be more than 2 meters.
The circulation pump of the DHW hot water recirculation system is small in size and has low power. Water recirculation in the DHW system is ensured by a circulation pump. The pump power is small, several tens of watts.
Pumps for DHW, unlike heating pumps, must have a maximum operating pressure at least 10 bar. Heating pumps often designed for a maximum pressure of no more than 6 bar. Another difference is that the DHW pump must have a hygienic certificate allowing use in drinking water supply systems.
The water in hot water supply systems is constantly renewed and the oxygen content in it remains quite high. Hot water is highly corrosive. In addition, hot water must correspond sanitary requirements To drinking water. Therefore, for making DHW pumps use corrosion-resistant non-ferrous metals or stainless steel. For these reasons, circulation pumps for hot water supply are noticeably more expensive than similar pumps for heating systems.
In some designs DHW pipelines It is possible to create natural water recirculation, without a pump.
As a result of water circulation in the DHW system hot water is constantly supplied to the sampling points.
In a DHW system with a storage heater and water recirculation, the water supply mode is more stable:
- Hot water is always present at the sampling points.
- Water can be collected simultaneously in several places. The temperature and pressure of water change slightly when the flow rate changes.
- You can take any, no matter how small, amount of hot water from the tap.
The recirculation circuit not only improves the comfort of water supply at remote points in the house, but also provides the ability to connect circuits to it heated floors in separate rooms. For example, in a bathroom, a water-heated floor will be comfortable all year round.
A DHW system with water recirculation constantly consumes energy for the operation of the circulation pump, as well as to compensate for heat losses in the boiler itself and in the pipes with circulating water. To reduce energy consumption, it is recommended to install a circulation pump with a built-in programmable timer that turns off water circulation during hours when it is not needed. The boiler and hot water pipes are insulated.
Disadvantages of a hot water supply system with a double-circuit gas boiler or water heater
Clocking of a double-circuit boiler in heating mode
As you know, a double-circuit gas boiler can provide a house with hot water and be a source of heat in the heating system. Hot water is prepared in a flow-through heat exchanger of the boiler. Read about the general disadvantages of a DHW system with a flow-through heater at the beginning of this article. But gas appliances with a flow-through heater have another problem - the difficulty of choosing the maximum power of a double-circuit boiler or hot water heater.
Most often it turns out that required power boiler for preparing hot water, significantly more power needed to heat all rooms in the house.
As already mentioned in the article above, to obtain hot water at the required temperature and its maximum flow rate, double-circuit gas boilers and hot water geysers have a fairly large maximum power, about 24 kW . or more. Boilers and heaters are equipped with automatic equipment, which can, by modulating the burner flame, reduce their power to a minimum, equal to approximately 30% of the maximum. Minimum dual-circuit power gas boiler or columns are usually around 8 kW. or more. This is the minimum boiler power, both in DHW and heating modes.
Gas burner of a double-circuit boiler or water heater due to design features cannot work stably with power less than the minimum (less than 8 kW.). At the same time, to work with the heating system of a private house or autonomous heating apartments, the boiler in heating mode should very often produce a power of less than 8 kW.
For example, power 8 kW. enough to provide heat to the premises of a house or apartment with an area of 80 - 110 m 2, and on the coldest five-day period heating season. In warmer periods, the productivity and power of the boiler should be significantly less.
Due to the fact that the boiler cannot operate below the minimum power, problems arise with adaptation (coordination) of a double-circuit boiler and heating system.
In small facilities with low heat consumption for heating, the boiler produces more heat than the heating system can accept. As a result of inconsistency between the parameters of the boiler and the system, the double-circuit boiler begins to operate in pulse mode, "beat"- as people say.
Working in “clocking” mode significantly reduces the service life of boiler parts and significantly reduces efficiency.
Clocking a gas boiler or water heater in DHW mode
Heating diagram tap water double-circuit gas boiler or hot water column, depending on the temperature ( T o C) and flow rate ( Q l/min) hot water. The thick line shows the boundaries of the Working Area. Gray zone, pos. 1 - clock zone boiler or column (switching between ON/OFF). For normal heating of water by a boiler or column, on the diagram the point of intersection of the lines of temperature and hot water flow (operating point) must always be inside working area, the boundaries of which are shown in the diagram with a thick line. If the hot water consumption mode is selected so that the operating point will be in the gray zone, pos. 1 on the diagram, then the boiler and column will clock. In this zone, with a small water flow, the power of the boiler or dispenser turns out to be excessive, the boiler, dispenser turns off due to overheating, and then turns on again. Either hot or cold water comes out of the tap.
Low efficiency of double-circuit gas boilers and water heaters
Double-circuit gas boilers when working with maximum power have an efficiency of more than 93%, and less than 80% when operating at minimum power. Imagine how the efficiency will further decrease if such a boiler has to operate in pulse mode, with the gas burner constantly re-igniting.
Please note that a double-circuit boiler operates at minimum power most of the time throughout the year. At least 1/4 of the spent gas will literally fly uselessly down the pipe. Add to this the cost of replacing prematurely worn-out boiler parts. This will be the price to pay for installing cheap heating and hot water equipment in your home.
What do you want - choose
If the power of a double-circuit gas boiler is more than 20 kW., selected based on maximum heating required flow hot water, then the boiler cannot provide economical and comfortable operation in mode low power heating and when heating water with low flow rates. The same can be said about the operation of a hot water column.
Most often, there is no need to prepare large flows of hot water in the house. For many people, it is much more important to ensure comfortable and economical use of hot water with low consumption.
For such thrifty owners, many manufacturers produce double-circuit gas boilers and water heaters with a maximum power of about 12 kW. and the minimum is less than 4 kW. Such boilers and heaters will provide more economical and comfortable heating and the use of hot water in quantities sufficient for taking a shower or washing dishes.
Before purchasing a double-circuit boiler or water heater, owners need to decide, which mode of hot water consumption is more profitable and comfortable - with a large water flow or with a small one. Based on this decision, choose the power of the boiler or dispenser. If you want both, you will have to choose a hot water supply system with a boiler.
For shower lovers, for preparing hot water and heating houses and apartments with a heated area of up to 140 m 2, with one bathroom power 12 kW. They best suit the needs of heating and hot water systems of small private houses and apartments.
For those who love to take a bath, as well as for houses and apartments large sizes, with an area of more than 140 m 2, I highly recommend using a single-circuit boiler.
Many manufacturers heating equipment release special kits, a boiler plus a built-in or remote boiler, just for such cases. Such a set of equipment will be more expensive, but will provide an increased service life of the equipment, gas savings and more comfortable use of hot water.
DHW circuit with sewerage heat recuperator
IN Western Europe and popular in the world various ways saving energy when operating a private home.
Hot water from the house flows down the drain after use and takes away with it a significant part of the thermal energy that was spent on heating it.
Scheme for the recovery of thermal energy from sewerage wastewater into the hot water supply system To reduce energy losses in the house, a scheme is used to recover (return) heat from sewage into the domestic hot water system of a private house.
Cold water passes through a heat exchanger before entering the DHW boiler. The wastewater from sanitary equipment is sent to the heat exchanger.
In the heat exchanger, two streams, cold water from the water supply and hot water from the wastewater, meet but do not mix. Some of the heat from hot water is transferred to cold water. The hot water boiler receives already heated water.
In the diagram shown in the figure, only those sanitary fixtures that operate with hot water flow are sent to the heat exchanger. This recovery scheme is advantageous to use with any method of heating water - both with a boiler and with a flow-through heater.
To recover heat from sanitary fixtures that first accumulate hot water, and then drain it into the sewer (bath, swimming pool, washing and dishwasher), apply more complex circuit with water circulation between the boiler and the heat exchanger while these devices are emptying.
For houses and apartments with permanent residence I highly recommend using it DHW system with a stratified heating boiler and a double-circuit boiler, or with an indirect heating boiler and a single-circuit boiler. The boiler volume is at least 100 liters. The system will provide good comfort use of hot water, economical consumption of gas and water, as well as a smaller volume of waste into the sewer. The only disadvantage of such a system is the higher cost of the equipment.
With a limited construction budget in small suburban areas country houses for seasonal stay You can install a hot water system with a flow-through heater.
It is advisable to use a DHW circuit with a flow-through heater in houses with a kitchen and one bathroom, where the heating source and hot water collection points are located compactly, at a short distance from each other. It is recommended to connect no more than three water taps to one instantaneous water heater.
The cost of such a system is relatively low, and the disadvantages of operation in this case are less pronounced. A double-circuit gas boiler or gas water heater takes up little space. Almost everything necessary equipment mounted in the device body. For installing a boiler with a capacity of up to 30 kW or a gas water heater does not require a separate room.
For preparing hot water and heating houses and apartments with a heated area of up to 140 m 2, with one shower in the bathroom, I recommend installing double-circuit gas boilers with maximum power 12 kW.
In a DHW system with a gas water heater or a double-circuit boiler the stability of the water supply mode will increase significantly if the circuit install a buffer tank between the heater and water collection points- a conventional storage electric water heater. It is especially recommended to install such a buffer storage electric water heater near distribution points remote from the gas appliance.
Read more: In a scheme with a buffer tank, hot water from a gas water heater or double-circuit boiler first enters the tank of an electric boiler - water heater. Thus, the tank always contains a supply of hot water. The electric heater in the tank only compensates for heat loss and maintains the required temperature of hot water during the period when there is no water supply. An electric water heater with a small capacity tank is enough - even 30 liters, and using hot water will become much more comfortable.
DHW system with instantaneous water heater and built-in boiler or remote layer-by-layer heating boiler will be slightly more expensive. But here you will not need to spend expensive electricity to maintain the water temperature, and the comfort of using water will be the same as with an indirect heating boiler.
In houses with branched DHW network
implement a scheme with a storage water heater (boiler) and water recirculation. Only such a scheme will provide the necessary comfort and economical operation DHW systems. True, the initial costs of its creation are the highest.
It is recommended to buy boilers that are sold complete with a boiler. In this case, the parameters of the boiler and boiler have already been correctly selected by the manufacturer, and most of the additional equipment is built into the boiler body.
If the heating in the house is provided by a solid fuel boiler, then it is beneficial to install, to which to connect a hot water supply system with water circulation.
Otherwise, to heat water in the house, connected to a solid fuel boilerindirect heating boiler, additionally equipped with an electric heater.
It is beneficial to use an electric hot water boiler in a house with a solid fuel boiler Often, only electricity is used to heat water in a house with a solid fuel boiler. For hot water supply in the house, near water points, a storage tank is installed electric boiler- water heater. There is no hot water circulation system in this option. It is more profitable to install your own separate storage heater near remote water collection points. In this case, electricity is spent more economically on heating water.
When heating water above 54 o C Hardness salts are released from the water. To reduce scale formation If possible, heat the water to a temperature lower than specified.
Instantaneous water heaters are especially sensitive to scale formation. If the water is hard, contains more than 140 mg CaCO 3 in 1 liter, then the use of instantaneous water heaters, including those with stratified heating boilers, for heating water is not recommended. Even small scale deposits clog the channels in flow heater
, which leads to the cessation of water flow through it.
It is recommended to supply water to the instantaneous water heater through an anti-scale filter, which reduces water hardness. The filter has a replaceable cartridge that will have to be changed regularly. For heating hard water, it is better to choose storage system DHW with indirect heating boiler. Salt deposits on heating element
the boiler does not impede the flow of water, but only reduces the performance of the boiler. The boiler is easier to clean from scale. It should be remembered that prolonged heating of water to a temperature of less than 60 o C can lead to the appearance of Legionella bacteria harmful to human health in the storage tank (boiler) with hot water. Recommended periodically perform thermal disinfection of the hot water system
, increasing the water temperature to 70 o C for some time.
More articles on this topic: In receipts for public utilities a new column has appeared - DHW. It caused confusion among users, since not everyone understands what it is and why it is necessary to make payments on this line. There are also apartment owners who cross out the box. This entails the accumulation of debt, penalties, fines and even litigation. In order not to take matters to extreme measures, you need to know what hot water supply is, DHW heat energy
and why you need to pay for these indicators.
What is DHW on the receipt?
DHW - this designation stands for hot water supply. Its goal is to provide apartments in apartment buildings and other residential premises with hot water at an acceptable temperature, but hot water supply is not the hot water itself, but the thermal energy that is spent on heating the water to an acceptable temperature.
- Central system. Here the water is heated at a heating station. After this, it is distributed to apartments in multi-apartment buildings.
- Autonomous system. It is usually used in private homes. The principle of operation is the same as in the central system, but here the water is heated in a boiler or boiler and is used only for the needs of one specific room.
Both systems have the same goal - to provide home owners with hot water. In apartment buildings, a central system is usually used, but many users install a boiler in case the hot water is turned off, as has happened more than once in practice. An autonomous system is installed where it is not possible to connect to the central water supply. Only those consumers who use the central heating system pay for hot water supply. Users of an autonomous circuit pay for utility resources that are spent to heat the coolant - gas or electricity.
Important! Another column in the receipt related to DHW is DHW at one unit. Decoding ODN - general house needs. This means that the DHW column on one unit is the expenditure of energy on heating water used for the general needs of all residents of an apartment building.
These include:
- technical work that is performed before the heating season;
- pressure testing of the heating system carried out after repair;
- repair work;
- heating of common areas.
Hot water law
The law on hot water supply was adopted in 2013. Government Resolution No. 406 states that users central system heating companies are required to pay according to a two-part tariff. This suggests that the tariff was divided into two elements:
- thermal energy;
- cold water.
This is how DHW appeared on the receipt, that is, the thermal energy spent on heating cold water. Housing and communal services specialists came to the conclusion that risers and heated towel rails, which are connected to the hot water supply circuit, consume thermal energy for heating non-residential premises. Until 2013, this energy was not taken into account in receipts, and consumers used it free of charge for decades, since the air in the bathroom continued to be heated outside the heating season. Based on this, officials divided the tariff into two components, and now citizens have to pay for hot water.
Water heating equipment
The equipment that heats the liquid is a water heater. Its breakdown does not affect the hot water tariff, but users are required to pay the cost of repairing the equipment, since water heaters are part of the property of homeowners in apartment building. The corresponding amount will appear in the receipt for the maintenance and repair of the property.
Important! This payment should be carefully considered by the owners of those apartments who do not use hot water, since their housing has a autonomous system heating. Housing and communal services specialists do not always pay attention to this, simply distributing the amount for water heater repairs among all citizens.
As a result, these apartment owners have to pay for equipment they did not use. If you discover an increase in the tariff for repairs and maintenance of property, you need to find out what this is connected with and contact management company for recalculation if the payment is calculated incorrectly.
Thermal energy component
What is this - a coolant component? This is heating cold water. The thermal energy component does not have a meter installed, unlike hot water. For this reason, it is impossible to calculate this indicator using a counter. How, in this case, is the thermal energy for hot water calculated? When calculating the payment, the following points are taken into account:
- tariff set for hot water supply;
- expenses spent on maintaining the system;
- cost of heat loss in the circuit;
- costs spent on coolant transfer.
Important! The cost of hot water is calculated taking into account the volume of water consumed, which is measured in 1 cubic meter.
The size of the energy fee is usually calculated based on the readings of the common hot water meter and the amount of energy in the hot water. Energy is calculated for each separate apartment. To do this, water consumption data is taken, which is learned from the meter readings, and multiplied by specific consumption thermal energy. The received data is multiplied by the tariff. This figure is the required contribution, which is indicated on the receipt.
How to make your own calculation
Not all users trust the payment center, which is why the question arises of how to calculate the cost of hot water supply yourself. The resulting figure is compared with the amount on the receipt and on the basis of this a conclusion is made about the correctness of the charges.
To calculate the cost of hot water supply, you need to know the tariff for thermal energy. The amount is also affected by the presence or absence of a meter. If there is one, then readings are taken from the meter. In the absence of a meter, the standard for the consumption of thermal energy used to heat water is taken. Such standard indicator An energy saving organization is being established.
If in multi-storey building an energy consumption meter is installed and the housing has a hot water meter, then the amount for hot water supply is calculated based on general house metering data and the subsequent proportional distribution of the coolant among apartments. If there is no meter, the rate of energy consumption per 1 cubic meter of water and the readings of individual meters are taken.
Complaint due to incorrect calculation of receipt
If, after independently calculating the amount of contributions for hot water supply, a difference is identified, you must contact the management company for clarification. If the organization's employees refuse to provide explanations on this matter, a written complaint must be submitted. Company employees have no right to ignore it. The response must be received within 13 working days.
Important! If no response is received or it is not clear from it why this situation arose, then the citizen has the right to file a claim with the prosecutor’s office or a statement of claim in court. The authority will consider the case and make an appropriate objective decision. You can also contact organizations that control the activities of the management company. Here the subscriber's complaint will be considered and an appropriate decision will be made.
Electricity used to heat water is not a free service. Payment for it is charged on the basis of the Housing Code Russian Federation. Each citizen can independently calculate the amount of this payment and compare the data obtained with the amount on the receipt. If any inaccuracy occurs, you should contact the management company. In this case, the difference will be compensated if the error is recognized.
Hot water heaters and heating heaters installed at consumer heating points require annual inspection and periodic repairs. At the end of the heating season, the heaters must be checked for tightness and, if a drop in pressure is detected, remove the rolls and inspect the tube sheets.
Hot water heater in fig. 1 - 26 is connected to the heating network in parallel with the heating system, therefore this connection scheme is called parallel.
The hot water heater consists of a housing and a tube bundle. In steam-water heaters, steam enters the upper part of the housing, and condensate is removed from the lower part of the housing. The heated water passes through the tubes. In water-water heaters, network water enters the housing on one side and leaves on the other. Water moving towards the network water inside the tubes goes into the hot water supply system.
Hot water heaters can operate with water pressure in housings and tubes up to 10 atm (g), and heating - in housings 7 atm and tubes 10 atm.
The absence of a hot water supply heater significantly simplifies and reduces the cost of equipping a consumer’s heating point. The consumer receives deaerated and softened water for water collection, which eliminates corrosion processes in hot water supply systems.
Automatic control of hot water supply heaters according to the described scheme can only be operational with parallel and mixed switching circuits. It could be either a regulator direct action type RR, or an indirect-acting regulator with a relay device type RD-Za or RDM. Setting up regulators in two-stage circuits is described in Chapter.
Switching hot water heaters from a sequential to a mixed circuit occurs when the outside air temperature rises, for example, for Moscow to 4 C.
When calculating hot water heaters, first of all, the permissible pressure loss for local water DY is established.
For the manufacture of hot water heaters, brass tubes 16X0 75 mm are used. The ends of the tubes are rolled into tube sheets. The heater consists of separate sections connected to each other by pipes and rolls. The number of sections and their diameter are selected depending on the heat consumption.
Currently, hot water heaters are manufactured without lens compensators. Heating heaters with brass tubes must have lens compensators, since in them hotter network water passes inside brass tubes, which have a higher coefficient of linear expansion than a steel body.
Heating units and hot water heaters must be equipped with automatic regulators, metering and control devices.
IN closed systems hot water heaters are connected to the heating network mainly using parallel, mixed and sequential schemes, which are used in both dependent and independent accession heating systems. The use of a particular scheme is determined by the ratio of the maximum load of hot water supply to rated heating, used in the area temperature chart central regulation release of heat received in subscriber consuming installations by the auto-regulation system.
There are three main schemes for connecting heat exchangers: parallel, mixed, series. The decision to apply a particular scheme is made design organization based on the requirements of SNiP and the supplier of heat coming from their energy capacities. In the diagrams, arrows show the passage of heating and heated water. In operating mode, the valves located in the heat exchanger jumpers must be closed.
1. Parallel circuit
2. Mixed scheme
3. Sequential (universal) circuit
When the DHW load significantly exceeds the heating load, hot water heaters are installed at heating point according to the so-called single-stage parallel circuit, in which the hot water heater is connected to the heating network parallel to the heating system. The constant temperature of tap water in the hot water supply system at the level of 55-60 ºС is maintained by a direct-acting RPD temperature regulator, which affects the flow of heating network water through the heater. At parallel connection network water consumption equal to the sum its costs for heating and hot water supply.
In a mixed two-stage scheme, the first stage of the DHW heater is connected in series with the heating system at return line network water, and the second stage is connected to the heating network in parallel with the heating system. In this case, preheating of tap water occurs due to cooling of network water after the heating system, which reduces thermal load second stage and reduces the total consumption of network water for hot water supply.
In a two-stage sequential (universal) circuit, both stages of the DHW heater are connected in series with the heating system: the first stage is after the heating system, the second is before the heating system. The flow regulator, installed parallel to the second stage of the heater, maintains constant the total flow of network water to the subscriber input, regardless of the flow of network water to the second stage of the heater. During the hours maximum loads DHW, all or most of the network water passes through the second stage of the heater, is cooled in it and enters the heating system at a temperature lower than the required one. In this case, the heating system does not receive enough heat. This undersupply of heat to the heating system is compensated during hours of low hot water supply loads, when the temperature of the network water entering the heating system is higher than that required for this outside temperature. In a two-stage sequential scheme, the total consumption of network water is less than in a mixed scheme, due to the fact that it uses not only the heat of network water after the heating system, but also the heat storage capacity of buildings. Reducing the consumption of network water helps to reduce the unit cost of external heating networks.
The connection diagram for hot water supply water heaters in closed heating supply systems is selected depending on the ratio of the maximum heat flow for hot water supply Qh max and the maximum heat flow for heating Qo max:
| 0,2 ≥ | Qh max | ≥ 1 - single-stage circuit |
| Qo max |
| 0,2 < | Qh max | < 1 - two-stage scheme |
| Qo ma |