For a comfortable stay in an apartment or a private house, a person needs water in the sanitary networks with certain temperature limits. This allows satisfying all generally accepted sanitary standards for personal hygiene procedures and for sanitary and technical needs. The temperature of the water in the faucet depends on the type of water supply and climatic factors. There are several types of technical solutions that allow to withstand the recommended temperature parameters in water intake systems.
The temperature of the water in the faucet depends on the climatic conditions, the depth of the water supply system, the location of the water intake, and so on.
Modern dwelling provides for the supply of cold and hot water to meet all needs. The temperature of the cold water in the tap has a regulation and can fluctuate within 5-15 ° C. The values of the temperature limit depend on such factors as:
- climatic conditions;
- depth of occurrence of water supply systems;
- temperature in the underground (basement communication networks);
- The place of water abstraction by water supply networks (rivers, canals, reservoirs, underground sources).
In order to check the water temperature, you need to use a special device that can be attached to the tap.
The temperature of cold water rises in the warm season and decreases in the cold. This statement is valid for typical schemes of water supply by a water canal, when it is taken from channel systems and reservoirs. Since the water mirror is warming up in summer, the amount of heat in the water masses, accordingly, changes. In the case of water supply from underground sources, the temperature regime remains practically constant throughout the year, due to the unchanged temperature in the underground water layers.
The amount of heat in water from cold water supply networks does not have a decisive impact on creating comfortable conditions in the sanitary and domestic sphere. Any housing involves a parallel supply of hot water, and by mixing the necessary heat is achieved.
Sanitary norms regulate the temperature of hot water in centralized networks of hot water supply within the range of 60-75 ° С. Deviation at night from 00.00 to 5.00 is allowed at 5 ° C and from 5.00 to 00.00 - at 3 ° C. These standards are justified by maintaining these values by boiler houses or central heating points (TSC). The calculated figures are based on the peculiarities of the boiler houses and heat exchangers of the central heating station and allow to correspond to the norms of microbiological indices in the DHW pipes. Drinking water is supplied only through cold water supply networks.
Disadvantages of DHW
In practice, the described temperature norms are not always maintained. This is due to a significant increase in the cost of natural resources (gas, coal, fuel oil), which are used as fuel in boiler houses. Boilers of the old model were calculated for supplying heat and hot water to hundreds of apartment buildings. Boilers have low efficiency, heating mains become unusable. Modern economic standards require the transition to the creation of mini-boiler houses.
Built-in hot water circuits.
One aspect of unsatisfactory hot water supply is the unevenness of the temperature regime. That is, the water in the tap becomes hot not immediately, its temperature rises as it passes through the system. This is due to the facts of dismantling of revolving sanitary systems in apartment buildings, due to their coming into disrepair and due to heat savings by heat generating companies.
Similar moments lead to the selection of an increased volume of water, which at a high price for supplied hot water is inappropriate. Municipal DHW networks use a specially prepared water reserve, in which various emollients have been added. Use it as drinking water can not.
The consumer prefers such conditions of DHW supply, under which hot water from the tap must be available all year round. Due to current repairs and frequent emergencies, it is almost impossible to achieve these conditions.
Scheme of indirect heater.
Availability of water from the tap with the desired temperature involves the use of various autonomous devices designed to warm up and maintain the desired values of heat.
There are several options for autonomous hot water preparation:
- use of electric water heaters of storage type (boilers);
- Use of combined boilers with piping with a heating boiler;
- application of electric flow heaters;
- the use of gas flow-through water heaters;
- application of double-circuit boilers (for heating and hot water);
- use of alternative sources for heating (solar cells, heat pumps).
The installation of electric water heaters, as a solution to the problem of non-compliance with temperature standards, is the most popular method for creating an autonomous hot water system. The advantages of this equipment is that it can be installed in almost any housing stock. Boilers do not require electrical networks with increased conductivity and power, allow connection to the wiring standards of the USSR. At the same time, they completely solve the problem of insufficient temperature of the water of municipal hot water. These devices work as a storage device, that is, a certain volume of water is heated to the desired temperature for the required time with the help of a TET.
Scheme of integration of the boiler into the heating system.
During water intake, cold water masses entering the boiler are squeezed out already heated, the feeding process lasts until the temperature decreases. Then it takes time to heat up the incoming water volume. As a rule, for 2-3 people it is enough to operate a boiler with a volume of 80-120 liters. To maintain the exact temperature at the point of intake, a thermostatic mixer can be installed.
The described boilers are also produced in a combined type. Inside their body is mounted a coil, through which the heat carrier of the heating boiler circulates. There is a double heating and using TEN, and with the help of heat extraction from the heating system. Such devices for DHW are used in private houses with gas single-circuit boilers, as an alternative to gas flow-through heaters.
- low power consumption;
- possibility of installation in any premises.
- inertness (relatively long heating time of the entire volume);
- impossibility of continuous use (limited by the capacity of the boiler).
Electric flow analogues
Scheme of electric instantaneous water heater.
Flow-through devices for raising the temperature of the hot water can produce an uninterrupted and hot water flow. But there are serious limitations. This equipment can not be installed in a conventional housing stock, since full-fledged and productive devices have a capacity of about 20 kW and require a three-phase connection. Single-phase heaters with a power of 3-5 kW have poor performance and can provide heating within Δt = 25-30 ° C, which will not create a comfortable heat when the cold flow is heated at a temperature of 3-5 ° C. Powerful heating devices are recommended for houses, cottages, mini-hotels, electric wiring of which is designed for these capacities.
- the creation of an uninterrupted hot flow (with the appropriate power);
- requires three-phase connection to the network and wiring the required cross-section for the specified capacity of the device.
Gas flow equipment (columns) makes it possible to obtain the hot water temperature practically in any limits and in any quantity, due to the heating of the gas stream by the gas burner passing through the copper heat exchanger. The power of the gas columns is 15-25 kW.
Restrictions for use may be residential buildings that are not equipped with chimneys for such equipment. Nevertheless, the old housing stock was equipped with gas heaters. These devices with modern technical solutions can very accurately regulate the set temperature, regardless of the flow rate of water. This technology is implemented by modulating the flame (changing its intensity, depending on the flow).
Diagram of a wall gas heater.
When drafting and approving the relevant services, it is possible to install gas heaters in multi-apartment buildings. In this case, often use devices with a closed type of burner, which provides insulation of the combustion chamber from the room. The air intake and flue gas discharge are forced, through a separately made chimney hole.
- high temperature delta of heating;
- Streaming mode of operation;
- the relative accuracy of the temperature at the output of the instrument.
- presence of natural gas;
- necessary technical conditions for installation and operation;
- installation in bathrooms is forbidden.
Double-circuit heating boiler
Scheme of connection of a double-circuit boiler with a storage tank.
Private double-walled boilers are widely used in private house-building and apartment buildings designed for the operation of autonomous heating sources. Hot water is produced in a secondary heat exchanger, in which heat is transferred from the heating system liquid to running tap water. As a result, water with the required temperature is formed at the outlet. The technical conditions for the operation of such devices correspond to the conditions for the use of gas flow-through type heaters.
- temperature accuracy;
- streaming mode of operation.
- availability of technical conditions for installation;
- The delta of heating is lower than that of the columns;
- inertness in work;
- rare cases of the possibility of installation in modern apartment buildings.
There are methods of heating water with the help of solar energy and heat pumps. The first method involves the transfer of solar energy into thermal energy using special tower and mirror installations. Currently in the CIS countries is not spread.
DHW from a boiler with an external boiler.
The second method involves the use of heat pumps operating on the principle of a refrigerating machine. The heat is taken from the air and transferred in special heat exchangers to the DHW circuit. This method is economically advantageous, but has limitations:
- can not be used in sub-zero temperatures;
- The water temperature in the DHW system is not more than 50 ° C.
Separately, it is necessary to say about cavitation water heating systems. The essence of their work is based on the flow of fluid through the vortex cavitator, resulting in its heating. This method is distinguished by economy, in comparison with the traditional thermal heating of a liquid. It is empirically proven that a different amount of energy is used to heat a cavitation method and a classical thermal method for a certain Δt of the same volume of water. In the first variant, 1 kW is used for the rotation of the cavitator, and in the second variant 1.7 kW is spent for the operation of the heaters.
To date, the method has received little spread, since it does not lack a number of shortcomings, such as:
- limited heating temperature;
- noise of the engine and cavitator;
- a small amount of special equipment is produced.
Application of thermostatic mixers
Thermostatic mixers are available for precise temperature control from a water tap.
The desired heat and pressure (pressure) are set on the handle of the mixer.
As a result of further operation of such a mixer, the temperature regime remains the same for small changes in the water supply network.
It is clear that this value can not be higher than the maximum heat of the supplied water from the DHW.
The principle of operation is based on the opening and closing of a mixing valve controlled by a bimetallic head that reacts to the temperature of the liquid.
Emergency situations associated with changes in the temperature of the tap water
Scheme of an induction boiler for heating water.
There are problems associated with an unjustified increase in the temperature of cold water in the aqueduct. And this effect can occur at any time of the year. Sometimes cold water does not warm slightly, by 5-10 ° C, but in some cases there can be noticeable warming of the water pipe.
Typically, such situations arise in multi-storey residential buildings, with centralized hot water supply. Mixing of aqueous media of hot and cold pipelines occurs, especially if the pressure in the pipeline of the hot pipeline is considerably higher than the pressure in the cold one.
The reason, in most cases, is caused by malfunction of the mixer on the riser. Less common errors in the performance of plumbing work locksmiths in the underground, because of what happens to hit the hot water in the cold highway.
The described supply fault must be eliminated in a short time period. The ingress of warm water into devices such as automatic washing machines and dishwashers can disable the control electronics, and the penetration of hot water into the flushing tank and further into the toilet sometimes causes its cracking due to a sharp temperature drop.
Structural diagram of the water heating system.
If an electric water heater is installed in an apartment and the central DHW is still in use, it is necessary to cut off the DHW circuit when using the heater and cut off the boiler when the water is withdrawn from the riser.
If two circuits are opened, then mixing will occur and in the worst case, a hydraulic shock may occur, which will lead to the destruction of plumbing fixtures or assemblies.
The operation of the gas flow-through water heater involves working without mixing cold water. That is, the temperature is set by changing the value of the degree of heating directly on the gas equipment.
In exceptional cases, admixture is allowed, only in the case of supplying the cold main to the heater with a separate branch through the collector at the input to the apartment. Neglect of this recommendation is fraught with the reduction of the water flow through the heat exchanger of the device, which will lead to overheating and emergency shutdown of the burners.
Recommendations for action
In the conditions of the old housing stock and the unstable operation of boiler houses or TSCs, there is often a situation where water from a hot tap comes with insufficient temperature.
Schematic diagram of a centralized water supply system.
The parameters of hot water are regulated on the basis of item 2.4. SanPiN 126.96.36.1996-09 "Hygienic requirements for ensuring the safety of hot water systems". In those cases when the supplied water is below the norm by more than 3 ° C, the payment should be reduced by 0.1% for each hour of underheating. If the temperature drops 40 ° C or lower, the payment corresponds to the tariffs for cold water (RF Government Decree No. 354 of 6 May 2011).
The main task is to contact an emergency service or a management company with a complaint about the delivery of hot water with insufficient temperature. After the appeal, a commission is created, which fixes the act that the water supplied does not meet the standards. A copy of the act remains with the claimant, in this case the resident who has applied to the management structures.
If the complaints are not followed by a reaction from the management company, it is required to draw up an act and sign it by at least two witnesses from the tenants and the chairman of the board of the apartment building. Then a written request is sent to the management company. Moreover, a copy of the submitted application with a mark of the accepted specialist should be kept. If, as a result of all complaints, competent authorities have not attempted to eliminate the causes of underheating, copies of documents may be grounds for applying to a court or a housing inspection.
As practice shows, it is quite difficult to prove the degree of underheating, such moments can be revealed later. The best solution is to switch to autonomous heating of water for sanitary and domestic needs. In terms of cost savings, the proposed solution can significantly reduce the cost of obtaining hot water.
The temperature of the water from the tap must comply with the standards described. These values allow the stand-alone equipment to operate at medium modes, and the consumer to receive water, the temperature of which allows it to be used for different tasks. The discrepancy of the water supplied by the central DHW with the sanitary norms is the reason for applying to the necessary authorities or preparing for switching to autonomous heating.