Looking through the statistics of visits to our blog, I noticed that search phrases such as, for example, appear very often “What should be the temperature of the coolant at minus 5 outside?”. Decided to post the old one. graph of quality regulation of heat supply based on the average daily outdoor temperature. I want to warn those who, on the basis of these figures, will try to sort out relations with the housing department or heating networks: the heating schedules for each individual settlement are different (I wrote about this in an article). Work on this schedule heating network in Ufa (Bashkiria).
I also want to draw attention to the fact that regulation occurs according to average daily outside temperature, so if, for example, outside at night minus 15 degrees, and during the day minus 5, then the coolant temperature will be maintained in accordance with the schedule minus 10 o C.
As a rule, the following temperature charts are used: 150/70 , 130/70 , 115/70 , 105/70 , 95/70 . The schedule is selected depending on the specific local conditions. House heating systems operate according to schedules 105/70 and 95/70. According to schedules 150, 130 and 115/70, main heat networks operate.
Let's look at an example of how to use the chart. Suppose the temperature outside is minus 10 degrees. Heating networks operate according to the temperature schedule 130/70 , which means at -10 o С the temperature of the heat carrier in the supply pipeline of the heating network must be 85,6 degrees, in the supply pipeline of the heating system - 70.8 o C with a schedule of 105/70 or 65.3 about C on a 95/70 schedule. The temperature of the water after the heating system must be 51,7 about S.
As a rule, the temperature values in the supply pipeline of heat networks are rounded off when setting the heat source. For example, according to the schedule, it should be 85.6 ° C, and 87 degrees are set at the CHP or boiler house.
Temperature outdoor air Tnv, o C |
Temperature of network water in the supply pipeline T1, about C |
Water temperature in the supply pipe of the heating system T3, about C |
Water temperature after heating system T2, about C |
|||
---|---|---|---|---|---|---|
150 | 130 | 115 | 105 | 95 | ||
8 | 53,2 | 50,2 | 46,4 | 43,4 | 41,2 | 35,8 |
7 | 55,7 | 52,3 | 48,2 | 45,0 | 42,7 | 36,8 |
6 | 58,1 | 54,4 | 50,0 | 46,6 | 44,1 | 37,7 |
5 | 60,5 | 56,5 | 51,8 | 48,2 | 45,5 | 38,7 |
4 | 62,9 | 58,5 | 53,5 | 49,8 | 46,9 | 39,6 |
3 | 65,3 | 60,5 | 55,3 | 51,4 | 48,3 | 40,6 |
2 | 67,7 | 62,6 | 57,0 | 52,9 | 49,7 | 41,5 |
1 | 70,0 | 64,5 | 58,8 | 54,5 | 51,0 | 42,4 |
0 | 72,4 | 66,5 | 60,5 | 56,0 | 52,4 | 43,3 |
-1 | 74,7 | 68,5 | 62,2 | 57,5 | 53,7 | 44,2 |
-2 | 77,0 | 70,4 | 63,8 | 59,0 | 55,0 | 45,0 |
-3 | 79,3 | 72,4 | 65,5 | 60,5 | 56,3 | 45,9 |
-4 | 81,6 | 74,3 | 67,2 | 62,0 | 57,6 | 46,7 |
-5 | 83,9 | 76,2 | 68,8 | 63,5 | 58,9 | 47,6 |
-6 | 86,2 | 78,1 | 70,4 | 65,0 | 60,2 | 48,4 |
-7 | 88,5 | 80,0 | 72,1 | 66,4 | 61,5 | 49,2 |
-8 | 90,8 | 81,9 | 73,7 | 67,9 | 62,8 | 50,1 |
-9 | 93,0 | 83,8 | 75,3 | 69,3 | 64,0 | 50,9 |
-10 | 95,3 | 85,6 | 76,9 | 70,8 | 65,3 | 51,7 |
-11 | 97,6 | 87,5 | 78,5 | 72,2 | 66,6 | 52,5 |
-12 | 99,8 | 89,3 | 80,1 | 73,6 | 67,8 | 53,3 |
-13 | 102,0 | 91,2 | 81,7 | 75,0 | 69,0 | 54,0 |
-14 | 104,3 | 93,0 | 83,3 | 76,4 | 70,3 | 54,8 |
-15 | 106,5 | 94,8 | 84,8 | 77,9 | 71,5 | 55,6 |
-16 | 108,7 | 96,6 | 86,4 | 79,3 | 72,7 | 56,3 |
-17 | 110,9 | 98,4 | 87,9 | 80,7 | 73,9 | 57,1 |
-18 | 113,1 | 100,2 | 89,5 | 82,0 | 75,1 | 57,9 |
-19 | 115,3 | 102,0 | 91,0 | 83,4 | 76,3 | 58,6 |
-20 | 117,5 | 103,8 | 92,6 | 84,8 | 77,5 | 59,4 |
-21 | 119,7 | 105,6 | 94,1 | 86,2 | 78,7 | 60,1 |
-22 | 121,9 | 107,4 | 95,6 | 87,6 | 79,9 | 60,8 |
-23 | 124,1 | 109,2 | 97,1 | 88,9 | 81,1 | 61,6 |
-24 | 126,3 | 110,9 | 98,6 | 90,3 | 82,3 | 62,3 |
-25 | 128,5 | 112,7 | 100,2 | 91,6 | 83,5 | 63,0 |
-26 | 130,6 | 114,4 | 101,7 | 93,0 | 84,6 | 63,7 |
-27 | 132,8 | 116,2 | 103,2 | 94,3 | 85,8 | 64,4 |
-28 | 135,0 | 117,9 | 104,7 | 95,7 | 87,0 | 65,1 |
-29 | 137,1 | 119,7 | 106,1 | 97,0 | 88,1 | 65,8 |
-30 | 139,3 | 121,4 | 107,6 | 98,4 | 89,3 | 66,5 |
-31 | 141,4 | 123,1 | 109,1 | 99,7 | 90,4 | 67,2 |
-32 | 143,6 | 124,9 | 110,6 | 101,0 | 94,6 | 67,9 |
-33 | 145,7 | 126,6 | 112,1 | 102,4 | 92,7 | 68,6 |
-34 | 147,9 | 128,3 | 113,5 | 103,7 | 93,9 | 69,3 |
-35 | 150,0 | 130,0 | 115,0 | 105,0 | 95,0 | 70,0 |
Please do not focus on the diagram at the beginning of the post - it does not correspond to the data from the table.
Method of calculation temperature graph described in the handbook (Chapter 4, p. 4.4, p. 153,).
This is quite laborious and long process, since for each outdoor temperature several values \u200b\u200bmust be considered: T 1, T 3, T 2, etc.
To our joy, we have a computer and a MS Excel spreadsheet. A colleague at work shared with me a ready-made table for calculating the temperature graph. She was once made by his wife, who worked as an engineer for a group of regimes in thermal networks.
In order for Excel to calculate and build a graph, it is enough to enter several initial values:
All. nothing more is required of you. The results of the calculations will be in the first table of the sheet. It is highlighted in bold.
The charts will also be rebuilt for the new values.
The table also considers the temperature of direct network water, taking into account wind speed.
The temperature graph represents the dependence of the degree of heating of water in the system on the temperature of cold outside air. After the necessary calculations, the result is presented in the form of two numbers. The first means the temperature of the water at the inlet to the heating system, and the second at the outlet.
For example, the entry 90-70ᵒС means that under given climatic conditions, for heating a certain building, it will be necessary that the coolant at the inlet to the pipes has a temperature of 90ᵒС, and at the outlet 70ᵒС.
All values are presented for the outside air temperature for the coldest five-day period. This design temperature is taken according to the joint venture " Thermal protection buildings." According to the norms, the internal temperature for residential premises is 20ᵒС. The schedule will ensure the correct supply of coolant to the heating pipes. This will avoid hypothermia of the premises and waste of resources.
The temperature schedule must be developed for each settlement. It allows you to provide the most competent work heating systems, namely:
Such calculations are necessary both for large heating stations and for boiler houses in small settlements. In this case, the result of calculations and constructions will be called the boiler house schedule.
Upon completion of the calculations, it is necessary to achieve the calculated degree of heating of the coolant. You can achieve it in several ways:
In the first case, the flow rate of water entering the heating network, in the second, the degree of heating of the coolant is regulated. The temporary option involves a discrete supply of hot liquid to the heating network.
For central system heat supply is most characteristic of high-quality, while the volume of water entering the heating circuit remains unchanged.
Depending on the purpose of the heating network, the execution methods differ. The first option is the normal heating schedule. It is a construction for networks that work only for space heating and are centrally regulated.
The increased schedule is calculated for heating networks that provide heating and hot water supply. It is built for closed systems and shows the total load on the hot water supply system.
The adjusted schedule is also intended for networks operating both for heating and for heating. Here, heat losses are taken into account when the coolant passes through the pipes to the consumer.
The constructed straight line depends on the following values:
To perform a competent calculation, it is necessary to calculate the difference between the water temperatures in the direct and return pipes Δt. The higher the value in the straight pipe, the better the heat transfer of the heating system and the higher the indoor temperature.
In order to rationally and economically consume the coolant, it is necessary to achieve the minimum possible value of Δt. This can be achieved, for example, by working on additional insulation external structures of the house (walls, coverings, ceilings over a cold basement or technical underground).
First of all, you need to get all the initial data. Standard values of temperatures of external and internal air are accepted according to the joint venture "Thermal protection of buildings". To find the power of heating devices and heat losses, you will need to use the following formulas.
In this case, the input data will be:
First of all, the actual resistance of the wall to heat transfer is found. In a simplified version, you can find it as a quotient of the wall thickness and its thermal conductivity. If a outdoor structure consists of several layers, individually find the resistance of each of them and add the resulting values.
Thermal losses of walls are calculated by the formula:
Q = F*(1/R 0)*(t inside air -t outside air)
Here Q is the heat loss in kilocalories and F is the surface area of the exterior walls. For more exact value it is necessary to take into account the area of the glazing and its heat transfer coefficient.
Specific (surface) power is calculated as a quotient maximum power device in W and heat transfer surface area. The formula looks like this:
R beats \u003d R max / F act
Based on the obtained values, temperature regime heating and a direct heat transfer is built. On one axis, the values of the degree of heating of the water supplied to the heating system are plotted, and on the other, the outside air temperature. All values are taken in degrees Celsius. The results of the calculation are summarized in a table in which the nodal points of the pipeline are indicated.
It is rather difficult to carry out calculations according to the method. To perform a competent calculation, it is best to use special programs.
For each building, such a calculation is carried out individually by the management company. For an approximate definition of water at the inlet to the system, you can use the existing tables.
The measures taken make it possible to determine the parameters of the coolant in the system in certain moment time. Analyzing the coincidence of the parameters with the graph, you can check the effectiveness heating system. The temperature chart table also indicates the degree of load on the heating system.
The temperature chart of the heating system 95 -70 degrees Celsius is the most demanded temperature chart. By and large, it can be said with certainty that all systems central heating work in this mode. The only exceptions are buildings with autonomous heating.
But also in autonomous systems there may be exceptions when using condensing boilers.
When using boilers operating on the condensation principle, the temperature curves of heating tend to be lower.
For example, at maximum load for a condensing boiler, there will be a mode of 35-15 degrees. This is due to the fact that the boiler extracts heat from the exhaust gases. In a word, with other parameters, for example, the same 90-70, it will not be able to work effectively.
Distinctive properties of condensing boilers are:
You have heard many times that the efficiency of a condensing boiler is about 108%. Indeed, the manual says the same thing.
But how can this be, because we are still with school desk taught that more than 100% does not happen.
You can see a photo of such a boiler a little higher, and a video with its operation can be easily found on the Internet.
It is safe to say that the heating temperature schedule of 95 - 70 is the most in demand.
This is explained by the fact that all houses that receive heat from central heat sources are designed to work in this mode. And we have more than 90% of such houses.
The principle of operation of such heat production occurs in several stages:
Advice. If you have a cooperative house or a society of co-owners of houses, then you can set up the elevator with your own hands, but this requires you to strictly follow the instructions and correctly calculate the throttle washer.
Very often we hear that people's heating does not work well and their rooms are cold.
There can be many reasons for this, the most common are:
A common mistake is an incorrectly dimensioned elevator nozzle. As a result, the function of mixing water and the operation of the entire elevator as a whole is disrupted.
This could happen for several reasons:
During the many years of operation of heating systems, people rarely think about the need to clean their heating systems. By and large, this applies to buildings that were built during the Soviet Union.
All heating systems must be hydropneumatic flushing in front of everyone heating season. But this is observed only on paper, since ZhEKs and other organizations carry out these works only on paper.
As a result, the walls of the risers become clogged, and the latter become smaller in diameter, which violates the hydraulics of the entire heating system as a whole. The amount of transmitted heat decreases, that is, someone simply does not have enough of it.
You can do hydropneumatic purge with your own hands, it is enough to have a compressor and a desire.
The same applies to cleaning radiators. Over many years of operation, radiators inside accumulate a lot of dirt, silt and other defects. Periodically, at least once every three years, they need to be disconnected and washed.
Dirty radiators greatly impair the heat output in your room.
The most common moment is an unauthorized change and redevelopment of heating systems. When replacing old metal pipes with metal-plastic ones, diameters are not observed. And sometimes various bends are added, which increases local resistance and worsens the quality of heating.
Very often, with such unauthorized reconstruction, the number of radiator sections also changes. And really, why not give yourself more sections? But in the end, your housemate, who lives after you, will receive less of the heat he needs for heating. And the last neighbor, who will receive less heat the most, will suffer the most.
An important role is played thermal resistance building envelopes, windows and doors. As statistics show, up to 60% of heat can escape through them.
As we said above, all water-jet elevators are designed to mix water from the supply line of heating networks into the return line of the heating system. Thanks to this process, system circulation and pressure are created.
As for the material used for their manufacture, both cast iron and steel are used.
Consider the principle of operation of the elevator in the photo below.
Through pipe 1, water from heating networks passes through the ejector nozzle and with high speed enters the mixing chamber 3. There, water is mixed with it from the return of the heating system of the building, the latter is supplied through pipe 5.
The resulting water is sent to the heating system supply through diffuser 4.
In order for the elevator to function correctly, it is necessary that its neck be correctly selected. To do this, calculations are made using the formula below:
Where ΔРnas is the design circulation pressure in the heating system, Pa;
Gcm - water consumption in the heating system kg / h.
Note!
True, for such a calculation, you need a building heating scheme.
When autumn confidently walks across the country, snow flies beyond the Arctic Circle, and in the Urals night temperatures stay below 8 degrees, then the word form “heating season” sounds appropriate. People recall past winters and try to figure out the normal temperature of the coolant in the heating system.
Prudent owners of individual buildings carefully revise the valves and nozzles of the boilers. Residents apartment building by October 1, they are waiting, like Santa Claus, a plumber from a management company. The ruler of valves and valves brings warmth, and with it - joy, fun and confidence in the future.
Megacities sparkle with high-rise buildings. A cloud of renovation hangs over the capital. Outback prays on five-story buildings. Until demolished, the house has a calorie supply system.
The economy class apartment building is heated through a centralized heat supply system. The pipes are included in basement buildings. The supply of heat carrier is regulated by inlet valves, after which water enters the mud collectors, and from there it is distributed through the risers, and from them it is supplied to the batteries and radiators that heat the dwelling.
The number of gate valves correlates with the number of risers. While doing repair work in a single apartment, it is possible to turn off one vertical, and not the whole house.
The spent liquid partially leaves through the return pipe, and partially is supplied to the hot water supply network.
Water for the heating configuration is prepared at a CHP plant or in a boiler house. The water temperature standards in the heating system are prescribed in building regulations ax: the component must be heated to 130-150 °C.
The supply is calculated taking into account the parameters of the outside air. So, for the South Ural region, minus 32 degrees is taken into account.
To prevent the liquid from boiling, it must be supplied to the network under a pressure of 6-10 kgf. But this is a theory. In fact, most networks operate at 95-110 ° C, since the network pipes of most settlements are worn out and high pressure tear them up like a heating pad.
An extensible concept is the norm. The temperature in the apartment is never equal to the primary indicator of the heat carrier. Here, the elevator unit performs an energy-saving function - a jumper between the direct and return pipes. The norms for the temperature of the coolant in the heating system on the return in winter allow the preservation of heat at a level of 60 ° C.
The liquid from the straight pipe enters the elevator nozzle, mixes with return water and again goes into the house network for heating. The carrier temperature is lowered by mixing the return flow. What affects the calculation of the amount of heat consumed by residential and utility rooms.
Hot water temperature sanitary rules at the points of analysis should lie in the range of 60-75 ° C.
In the network, the coolant is supplied from the pipe:
A temperature chart is drawn up. Average daily temperature return water should not exceed the schedule by more than 5% at night and 3% during the day.
One of the details of warming a home is a riser through which the coolant enters the battery or radiator from the temperature norms of the coolant in the heating system require heating in the riser in winter time in the range of 70-90 °C. In fact, the degrees depend on the output parameters of the CHP or boiler house. In the summer, when hot water is needed only for washing and showering, the range moves to the range of 40-60 ° C.
Observant people may notice that in a neighboring apartment, the heating elements are hotter or colder than in his own.
The reason for the temperature difference in the heating riser is the way the hot water is distributed.
In a single-pipe design, the heat carrier can be distributed:
In a two-pipe system, the degree is the same throughout, theoretically 90 ° C in the forward direction and 70 ° C in the opposite direction.
Suppose that the structures of the central network are reliably insulated along the entire route, the wind does not walk through the attics, stairwells and basements, the doors and windows in the apartments are insulated by conscientious owners.
We assume that the coolant in the riser complies with the building regulations. It remains to find out what is the norm for the temperature of the heating batteries in the apartment. The indicator takes into account:
Therefore, attention: it is important, not what is the degree of the heater, but what is the degree of air in the room.
During the day in the corner rooms, the thermometer should show at least 20 ° C, and in the centrally located rooms 18 ° C is allowed.
At night, air in the dwelling is allowed to be 17 ° C and 15 ° C, respectively.
The name "battery" is household, denoting a number of identical items. In relation to the heating of housing, this is a series of heating sections.
The temperature standards of heating batteries allow heating no higher than 90 ° C. According to the rules, parts heated above 75 ° C are protected. This does not mean that they need to be sheathed with plywood or bricked. Usually they put a lattice fence that does not interfere with air circulation.
Cast iron, aluminum and bimetallic devices are common.
Aesthetics cast iron radiators- a parable in the language. They require periodic painting, as the regulations require that the work surface should have a smooth surface and allow dust and dirt to be easily removed.
A dirty coating forms on the rough inner surface of the sections, which reduces the heat transfer of the device. But the technical parameters cast iron products on high:
Another type of radiators is made of aluminum. Lightweight construction, painted in the factory, does not require painting, easy to clean.
But there is a drawback that overshadows the advantages - corrosion in aquatic environment. Certainly, inner surface heaters are insulated with plastic to avoid contact of aluminum with water. But the film may be damaged, then it will begin chemical reaction with the release of hydrogen, when creating overpressure gas aluminum appliance may burst.
The temperature standards of heating radiators are subject to the same rules as batteries: it is not so much heating that matters metal object how much air heating in the room.
In order for the air to warm up well, there must be sufficient heat removal from working surface heating structure. Therefore, it is strongly not recommended to increase the aesthetics of the room with shields in front of the heating device.
Since we are talking about apartment building, then it should be mentioned stairwells. The norms for the temperature of the coolant in the heating system state: the degree measure on the sites should not fall below 12 ° C.
Of course, the discipline of the tenants requires that the doors be closed tightly. entrance group, do not leave the transoms of stair windows open, keep the glass intact and promptly report any problems to the management company. If the management company does not take timely measures to insulate the points of probable heat loss and maintain the temperature regime in the house, an application for recalculation of the cost of services will help.
Replacement of existing heating devices in the apartment is carried out with the obligatory coordination with the management company. Unauthorized change in the elements of warming radiation can disrupt the thermal and hydraulic balance of the structure.
The heating season will begin, a change in the temperature regime in other apartments and sites will be recorded. Technical inspection premises will reveal unauthorized changes in the types of heating devices, their number and size. The chain is inevitable: conflict - trial - fine.
So the situation is resolved like this:
Let us recall once again that the heat supply network of an apartment building is equipped with heat energy metering units, which record both the consumed gigacalories and the cubic capacity of water passed through the house line.
In order not to be surprised by bills containing unrealistic amounts for heat at temperatures in the apartment below the norm, before the start of the heating season, check with the management company whether the meter is in working order, whether the verification schedule has been violated.
Looking through the statistics of visiting our blog, I noticed that search phrases such as, for example, “what should be the temperature of the coolant at minus 5 outside?” appear very often. I decided to lay out the old schedule for the quality regulation of heat supply based on the average daily outdoor temperature. I want to warn those who, on the basis of these figures, will try to sort out relations with the housing department or heating networks: the heating schedules for each individual settlement are different (I wrote about this in the article on regulating the temperature of the coolant). Thermal networks in Ufa (Bashkiria) operate according to this schedule.
I also want to draw attention to the fact that regulation takes place according to the average daily outdoor temperature, so if, for example, it is minus 15 degrees outside at night and minus 5 during the day, then the coolant temperature will be maintained in accordance with the schedule at minus 10 °C.
As a rule, the following temperature graphs are used: 150/70, 130/70, 115/70, 105/70, 95/70. The schedule is selected depending on the specific local conditions. House heating systems operate according to schedules 105/70 and 95/70. According to schedules 150, 130 and 115/70, main heat networks operate.
Let's look at an example of how to use the chart. Suppose the temperature outside is minus 10 degrees. Heating networks operate according to a temperature schedule of 130/70, which means that at -10 ° C the temperature of the coolant in the supply pipeline of the heating network should be 85.6 degrees, in the supply pipeline of the heating system - 70.8 ° C with a schedule of 105/70 or 65.3 ° C at chart 95/70. The water temperature after the heating system should be 51.7 °C.
As a rule, the temperature values in the supply pipeline of heat networks are rounded off when setting the heat source. For example, according to the schedule, it should be 85.6 ° C, and 87 degrees are set at the CHP or boiler house.
53,2 | 50,2 | 46,4 | 43,4 | 41,2 | 35,8 |
55,7 | 52,3 | 48,2 | 45,0 | 42,7 | 36,8 |
58,1 | 54,4 | 50,0 | 46,6 | 44,1 | 37,7 |
60,5 | 56,5 | 51,8 | 48,2 | 45,5 | 38,7 |
62,9 | 58,5 | 53,5 | 49,8 | 46,9 | 39,6 |
65,3 | 60,5 | 55,3 | 51,4 | 48,3 | 40,6 |
67,7 | 62,6 | 57,0 | 52,9 | 49,7 | 41,5 |
70,0 | 64,5 | 58,8 | 54,5 | 51,0 | 42,4 |
72,4 | 66,5 | 60,5 | 56,0 | 52,4 | 43,3 |
74,7 | 68,5 | 62,2 | 57,5 | 53,7 | 44,2 |
77,0 | 70,4 | 63,8 | 59,0 | 55,0 | 45,0 |
79,3 | 72,4 | 65,5 | 60,5 | 56,3 | 45,9 |
81,6 | 74,3 | 67,2 | 62,0 | 57,6 | 46,7 |
83,9 | 76,2 | 68,8 | 63,5 | 58,9 | 47,6 |
86,2 | 78,1 | 70,4 | 65,0 | 60,2 | 48,4 |
88,5 | 80,0 | 72,1 | 66,4 | 61,5 | 49,2 |
90,8 | 81,9 | 73,7 | 67,9 | 62,8 | 50,1 |
93,0 | 83,8 | 75,3 | 69,3 | 64,0 | 50,9 |
95,3 | 85,6 | 76,9 | 70,8 | 65,3 | 51,7 |
97,6 | 87,5 | 78,5 | 72,2 | 66,6 | 52,5 |
99,8 | 89,3 | 80,1 | 73,6 | 67,8 | 53,3 |
102,0 | 91,2 | 81,7 | 75,0 | 69,0 | 54,0 |
104,3 | 93,0 | 83,3 | 76,4 | 70,3 | 54,8 |
106,5 | 94,8 | 84,8 | 77,9 | 71,5 | 55,6 |
108,7 | 96,6 | 86,4 | 79,3 | 72,7 | 56,3 |
110,9 | 98,4 | 87,9 | 80,7 | 73,9 | 57,1 |
113,1 | 100,2 | 89,5 | 82,0 | 75,1 | 57,9 |
115,3 | 102,0 | 91,0 | 83,4 | 76,3 | 58,6 |
117,5 | 103,8 | 92,6 | 84,8 | 77,5 | 59,4 |
119,7 | 105,6 | 94,1 | 86,2 | 78,7 | 60,1 |
121,9 | 107,4 | 95,6 | 87,6 | 79,9 | 60,8 |
124,1 | 109,2 | 97,1 | 88,9 | 81,1 | 61,6 |
126,3 | 110,9 | 98,6 | 90,3 | 82,3 | 62,3 |
128,5 | 112,7 | 100,2 | 91,6 | 83,5 | 63,0 |
130,6 | 114,4 | 101,7 | 93,0 | 84,6 | 63,7 |
132,8 | 116,2 | 103,2 | 94,3 | 85,8 | 64,4 |
135,0 | 117,9 | 104,7 | 95,7 | 87,0 | 65,1 |
137,1 | 119,7 | 106,1 | 97,0 | 88,1 | 65,8 |
139,3 | 121,4 | 107,6 | 98,4 | 89,3 | 66,5 |
141,4 | 123,1 | 109,1 | 99,7 | 90,4 | 67,2 |
143,6 | 124,9 | 110,6 | 101,0 | 94,6 | 67,9 |
145,7 | 126,6 | 112,1 | 102,4 | 92,7 | 68,6 |
147,9 | 128,3 | 113,5 | 103,7 | 93,9 | 69,3 |
150,0 | 130,0 | 115,0 | 105,0 | 95,0 | 70,0 |
Please do not focus on the diagram at the beginning of the post - it does not correspond to the data from the table.
The method for calculating the temperature graph is described in the handbook "Setting up and operation of water heating networks" (Chapter 4, p. 4.4, p. 153,).
This is a rather laborious and lengthy process, since several values must be read for each outdoor temperature: T1, T3, T2, etc.
To our joy, we have a computer and a MS Excel spreadsheet. A colleague at work shared with me a ready-made table for calculating the temperature graph. She was once made by his wife, who worked as an engineer for a group of regimes in thermal networks.
Table for calculating the temperature graph in MS Excel
In order for Excel to calculate and build a graph, it is enough to enter several initial values:
Entering initial data into the table for calculating the temperature graph
All. nothing more is required of you. The results of the calculations will be in the first table of the sheet. It is highlighted in bold.
The charts will also be rebuilt for the new values.
Graphical representation of the temperature graph
The table also considers the temperature of direct network water, taking into account wind speed.
Download temperature chart calculation
energoworld.com
Design temperature outdoor | Water temperature in server pipeline | Water temperature in return pipeline | Estimated outdoor temperature | Supply water temperature | Water temperature in return pipeline |
CLOSED HEATING SYSTEM
TV1: G1 = 1V1; G2=G1; Q = G1(h2 –h3)
OPEN HEATING SYSTEM
WITH WATER TANK INTO A DEAD-END DHW SYSTEM
TV1: G1 = 1V1; G2 = 1V2; G3 = G1 - G2;
Q1 \u003d G1 (h2 - h3) + G3 (h3 - hх)
Bibliography
1. Gershunsky B.S. Fundamentals of electronics. Kyiv, Vishcha school, 1977.
2. Meyerson A.M. Radio-measuring equipment. - Leningrad.: Energy, 1978. - 408s.
3. Murin G.A. Thermotechnical measurements. -M.: Energy, 1979. -424 p.
4. Spector S.A. Electrical measurements physical quantities. Tutorial. - Leningrad.: Energoatomizdat, 1987. –320s.
5. Tartakovskii D.F., Yastrebov A.S. Metrology, standardization and technical measuring instruments. - M .: Higher school, 2001.
6. Heat meters TSK7. Manual. - St. Petersburg.: CJSC TEPLOKOM, 2002.
7. Calculator of the amount of heat VKT-7. Manual. - St. Petersburg.: CJSC TEPLOKOM, 2002.
Zuev Alexander Vladimirovich
Neighboring files in the Process Measurements and Instruments folder
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The task of organizations servicing houses and buildings is to maintain standard temperature. The temperature curve of heating directly depends on the temperature outside.
AT Soviet times when everything was state-owned, all the parameters of the temperature charts were maintained. If according to the schedule there should be a supply temperature of 100 degrees, then this will be so. Such a temperature cannot be supplied to residents, so elevator units were designed. Water from the return pipeline, cooled down, was mixed into the supply system, thereby lowering the supply temperature to the standard one. In our time of universal economy, the need for elevator nodes is no longer necessary. All heat supply organizations switched to the temperature chart of the heating system 95/70. According to this graph, the coolant temperature will be 95 °C when the outside temperature is -35 °C. As a rule, the temperature at the entrance to the house no longer requires dilution. Therefore, all elevator units must be eliminated or reconstructed. Instead of conical sections that reduce both the speed and volume of the flow, put straight pipes. Seal the supply pipe from the return pipeline with a steel plug. This is one of the heat saving measures. It is also necessary to insulate the facades of houses, windows. Change old pipes and batteries to new ones - modern ones. These measures will increase the air temperature in dwellings, which means you can save on heating temperature. Lowering the temperature on the street is immediately reflected in the residents in the receipts.
Most Soviet cities were built with an "open" heating system. This is when water from the boiler room comes directly to consumers in homes and is used for personal needs of citizens and heating. During the reconstruction of systems and the construction of new heating systems, a "closed" system is used. The water from the boiler house reaches the heating point in the microdistrict, where it heats the water to 95 °C, which goes to the houses. It turns out two closed rings. This system allows heat supply organizations to significantly save resources for heating water. Indeed, the volume of heated water leaving the boiler room will be almost the same at the entrance to the boiler room. No need to get into the system cold water.
How to carry out the temperature heating schedule. It is possible in three ways:
The quantitative method prevails, which is not always able to withstand the heating temperature graph.
Fight against heat supply organizations. This struggle is waged by management companies. By law Management Company is obliged to conclude an agreement with the heat supply organization. Will it be a contract for the supply of heat resources or just an agreement on interaction, the management company decides. An annex to this agreement will be a temperature schedule for heating. The heat supply organization is obliged to approve the temperature schemes in the city administration. The heat supply organization supplies the heat resource to the wall of the house, that is, to the metering stations. By the way, the legislation establishes that thermal workers are obliged to install metering stations in houses at their own expense with an installment payment for residents. So, having metering devices at the entrance and exit from the house, you can control the heating temperature daily. We take the temperature table, look at the air temperature on the weather site and find in the table the indicators that should be. If there are deviations, you need to complain. Even if the deviations are higher, residents will pay more. At the same time, the windows will be opened and the rooms will be ventilated. It is necessary to complain about insufficient temperature to the heat supply organization. If there is no response, we write to the city administration and Rospotrebnadzor.
Until recently, there was a multiplying coefficient on the cost of heat for residents of houses that were not equipped with common house meters. Due to the sluggishness of managing organizations and thermal workers, ordinary residents suffered.
Important indicator in the heating temperature chart is the return temperature of the network. In all graphs, this is an indicator of 70 ° C. In severe frosts, when heat losses increase, heat supply organizations are forced to turn on additional pumps on the return pipeline. This measure increases the speed of water movement through the pipes, and, therefore, the heat transfer increases, and the temperature in the network is maintained.
Again, during the period of general savings, it is very problematic to force thermal workers to turn on additional pumps, which means increasing electricity costs.
The heating temperature graph is calculated based on the following indicators:
For different rooms temperature curve is different. For children's institutions (schools, gardens, palaces of art, hospitals), the temperature in the room should be between +18 and +23 degrees according to sanitary and epidemiological standards.
It is easier to calculate the temperature schedule for a private house, since the equipment is mounted right in the house. A zealous owner will provide heating to the garage, bathhouse, and outbuildings. The load on the boiler will increase. Counting heat load depending on the maximum low air temperatures of past periods. We select equipment by power in kW. The most cost-effective and environmentally friendly boiler is natural gas. If gas is brought to you, this is already half the battle done. You can also use bottled gas. At home, you do not have to adhere to standard temperature schedules of 105/70 or 95/70, and it does not matter that the temperature in the return pipeline is not 70 ° C. Adjust the network temperature to your liking.
By the way, many city dwellers would like to put individual counters on the heat and control the temperature chart yourself. Contact the heat supply companies. And there they hear such answers. Most of the houses in the country are built on a vertical heating system. Water is supplied from the bottom - up, less often: from top to bottom. With such a system, the installation of heat meters is prohibited by law. Even if a specialized organization installs these meters for you, the heat supply organization simply will not accept these meters for operation. That is, savings will not work. Installation of meters is possible only with horizontal heating distribution.
In other words, when a heating pipe comes into your home not from above, not from below, but from the entrance corridor - horizontally. At the place of entry and exit of heating pipes, individual heat meters can be installed. Installation of such counters pays off in two years. All houses are now being built with just such a wiring system. Heating appliances are equipped with control knobs (taps). If the temperature in the apartment is high in your opinion, then you can save money and reduce the heating supply. Only ourselves we will save from freezing.
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The temperature chart of the heating system 95 -70 degrees Celsius is the most demanded temperature chart. By and large, we can say with confidence that all central heating systems operate in this mode. The only exceptions are buildings with autonomous heating.
But even in autonomous systems there may be exceptions when using condensing boilers.
When using boilers operating on the condensation principle, the temperature curves of heating tend to be lower.
Temperature in pipelines depending on the outside air temperature
For example, at maximum load for a condensing boiler, there will be a mode of 35-15 degrees. This is due to the fact that the boiler extracts heat from the exhaust gases. In a word, with other parameters, for example, the same 90-70, it will not be able to work effectively.
Distinctive properties of condensing boilers are:
You have heard many times that the efficiency of a condensing boiler is about 108%. Indeed, the manual says the same thing.
Condensing boiler Valliant
But how can this be, because we were taught from the school desk that more than 100% does not happen.
You can see a photo of such a boiler a little higher, and a video with its operation can be easily found on the Internet.
Principle of operation
It is safe to say that the heating temperature schedule of 95 - 70 is the most in demand.
This is explained by the fact that all houses that receive heat from central heat sources are designed to work in this mode. And we have more than 90% of such houses.
District boiler house
The principle of operation of such heat production occurs in several stages:
Advice. If you have a cooperative house or a society of co-owners of houses, then you can set up the elevator with your own hands, but this requires you to strictly follow the instructions and correctly calculate the throttle washer.
Very often we hear that people's heating does not work well and their rooms are cold.
There can be many reasons for this, the most common are:
A common mistake is an incorrectly dimensioned elevator nozzle. As a result, the function of mixing water and the operation of the entire elevator as a whole is disrupted.
This could happen for several reasons:
During the many years of operation of heating systems, people rarely think about the need to clean their heating systems. By and large, this applies to buildings that were built during the Soviet Union.
All heating systems must undergo hydropneumatic flushing before each heating season. But this is observed only on paper, since ZhEKs and other organizations carry out these works only on paper.
As a result, the walls of the risers become clogged, and the latter become smaller in diameter, which violates the hydraulics of the entire heating system as a whole. The amount of transmitted heat decreases, that is, someone simply does not have enough of it.
You can do hydropneumatic purge with your own hands, it is enough to have a compressor and a desire.
The same applies to cleaning radiators. Over many years of operation, radiators inside accumulate a lot of dirt, silt and other defects. Periodically, at least once every three years, they need to be disconnected and washed.
Dirty radiators greatly impair the heat output in your room.
The most common moment is an unauthorized change and redevelopment of heating systems. When replacing old metal pipes with metal-plastic ones, diameters are not observed. And sometimes various bends are added, which increases local resistance and worsens the quality of heating.
Metal-plastic pipe
Very often, with such unauthorized reconstruction and replacement of heating batteries with gas welding, the number of radiator sections also changes. And really, why not give yourself more sections? But in the end, your housemate, who lives after you, will receive less of the heat he needs for heating. And the last neighbor, who will receive less heat the most, will suffer the most.
An important role is played by the thermal resistance of building envelopes, windows and doors. As statistics show, up to 60% of heat can escape through them.
As we said above, all water-jet elevators are designed to mix water from the supply line of heating networks into the return line of the heating system. Thanks to this process, system circulation and pressure are created.
As for the material used for their manufacture, both cast iron and steel are used.
Consider the principle of operation of the elevator in the photo below.
The principle of operation of the elevator
Through branch pipe 1, water from heating networks passes through the ejector nozzle and enters the mixing chamber 3 at high speed. There, water from the return of the building's heating system is mixed with it, the latter is supplied through branch pipe 5.
The resulting water is sent to the heating system supply through diffuser 4.
In order for the elevator to function correctly, it is necessary that its neck be correctly selected. To do this, calculations are made using the formula below:
Where ΔРnas - design circulation pressure in the heating system, Pa;
Gcm - water consumption in the heating system kg / h.
Note! True, for such a calculation, you need a building heating scheme.
Appearance elevator node
Have a warm winter!
In this article, we will find out how average daily temperature when designing heating systems, how the temperature of the coolant at the outlet of the elevator unit depends on the temperature outside and what the temperature of the heating batteries can be in winter.
We will touch on the topic self fight cold in the apartment.
Cold in winter is a sore subject for many residents of city apartments.
Here we present the main provisions and excerpts from the current SNiP.
The design temperature of the heating period, which is included in the design of heating systems, is nothing less than the average temperature of the coldest five-day periods for the eight coldest winters of the last 50 years.
This approach allows, on the one hand, to be prepared for severe frosts that occur only once every few years, and on the other hand, not to invest excessive funds in the project. On the scale of mass construction, we are talking about very significant amounts.
It should be noted right away that the temperature in the room is affected not only by the temperature of the coolant in the heating system.
Several factors are at work in parallel:
It is curious: now there has been a trend towards the construction of apartment buildings with the maximum degree of thermal insulation. In Crimea, where the author lives, new houses are being built immediately with facade insulation mineral wool or polystyrene and with hermetically closing doors of entrances and apartments.
The facade is covered from the outside with basalt fiber slabs.
So, what are the current temperature standards in rooms for various purposes?
For obvious reasons, the heat in the gym is useless.
What should be the temperature of the water in the heating pipes?
It is determined by four factors:
The convector somewhat loses to the radiator in terms of thermal efficiency.
So, what should be the temperature of heating - water in the supply and return pipes - at different outdoor temperatures?
We present only a small part temperature table for the estimated ambient temperature of -40 degrees.
To understand the principle of operation of the heating system of an apartment building, the division of areas of responsibility, you need to know a few more facts.
The temperature of the heating main at the outlet from the CHP and the temperature of the heating system in your home are completely different things. At the same -40, a CHP or boiler house will produce about 140 degrees at the supply. Water does not evaporate only due to pressure.
In the elevator unit of your house, part of the water from the return pipeline, returning from the heating system, is mixed into the supply. The nozzle injects a jet of hot water at high pressure into the so-called elevator and recirculates the masses of cooled water.
Schematic diagram of the elevator.
Why is this needed?
To provide:
Attention: for kindergartens, a different temperature norm applies: no higher than 37C. low temperature heating appliances have to be compensated large area heat exchange. That is why in kindergartens the walls are decorated with radiators of such great length.
If you stop the suction of water from the return, the circulation will become so slow that the return pipeline can simply freeze in winter.
The areas of responsibility are divided as follows:
Such a state of heating mains, as in the photo, means huge heat losses. This is the area of responsibility of the KTS.
If your house is cold and all the heating devices are those installed by the builders, you will settle this issue with the residents. They are required to provide the temperatures recommended by sanitary standards.
If you undertake any modification of the heating system, for example, replacing the heating batteries with gas welding, you thereby assume full responsibility for the temperature in your home.
Let us, however, be realistic: most often we have to solve the problem of cold in the apartment ourselves, with our own hands. Not always housing organization can provide you with warmth in a reasonable time, and sanitary norms not everyone will be satisfied: I want the house to be warm.
What will the instructions for dealing with cold in an apartment building look like?
There are jumpers in front of the heaters in most apartments, which are designed to ensure the circulation of water in the riser in any condition of the radiator. For a long time they were supplied three-way valves, then they began to be installed without any shut-off valves.
The jumper in any case reduces the circulation of the coolant through heater. In the case when its diameter is equal to the diameter of the eyeliner, the effect is especially pronounced.
The simplest way to make your apartment warmer is to insert chokes into the jumper itself and the connection between it and the radiator.
Here, ball valves perform the same function. It's not entirely correct, but it will work.
With their help, it is possible to conveniently adjust the temperature of the heating batteries: when the jumper is closed and the throttle to the radiator is fully open, the temperature is maximum, it is worth opening the jumper and covering the second throttle - and the heat in the room comes to naught.
The great advantage of such a refinement is the minimum cost of the solution. The price of the throttle does not exceed 250 rubles; spurs, couplings and locknuts cost a penny at all.
Important: if the throttle leading to the radiator is at least slightly covered, the throttle on the jumper opens completely. Otherwise, adjusting the heating temperature will result in batteries and convectors that have cooled down at the neighbors.
Another helpful change. With such a tie-in, the radiator will always be evenly hot along the entire length.
Even if the radiator in the room hangs on a return riser with a temperature of about 40 degrees, by modifying the heating system, you can make the room warm.
An output - low-temperature systems of heating.
In a city apartment, it is difficult to use underfloor heating convectors due to the limited height of the room: raising the floor level by 15-20 centimeters will mean completely low ceilings.
Much more real option- warm floor. Due to where larger area heat transfer and more rational distribution of heat in the volume of the room low temperature heating warms up the room better than a hot radiator.
What does the implementation look like?
So that communications do not spoil appearance rooms, they are put away in a box. As an option, the tie-in to the riser is moved closer to the floor level.
It is not a problem at all to transfer the valves and throttles to any convenient place.
Additional information about work centralized systems heating you can find in the video at the end of the article. warm winters!
The building heating system is the heart of all engineering and technical mechanisms of the whole house. Which of its components will be selected will depend on:
Selection of sections for the room
All of the above qualities directly depend on:
One of the main points is the selection and calculation of sections of heating radiators. In most cases, the number of sections is calculated by design organizations that develop a complete project for building a house.
This calculation is affected by:
The data for the calculation are taken from the SNiP "Construction Climatology". The calculation of the number of sections of heating radiators according to SNiP is very accurate, thanks to which you can perfectly calculate the heating system.
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