Technical Field

The invention relates to a method of regulating the temperature of water, specifically to a method of regulating the temperature of domestic hot water circulating in the heating circulation system of the central domestic hot water heating system to at least one consumption point, and the heating system for its implementation.

State of the Art

Central heating of domestic hot water (hereinafter DHW) is used in buildings and industrial solutions, which reduce the costs of the heating system. This is then one for an entire building (system), Centrally prepared hot water is distributed to individual consumption points (users). However, this solution brings an increase in heating costs, because the DHW line is burdened with losses, which represent a 60% increase in the heating costs of the whole of the DHW.

Currently, heating circulation systems are known for bringing of domestic hot water to individual consumption points, where the temperature of the water in the domestic hot water storage tank Is set precisely, with the water from the storage tank flawing through the circulation system towards the individual consumption points. Therefore, in order for the water to reliably have the required temperature at the individual consumption points, the water in these systems must keep circulating through the heating circulation system, In the course of circulation, the water gradually loses its temperature and must therefore be constantly reheated in the tank. This is very demanding on energy consumption.

Timed cycling of hot water circulation through the heating circulation system is used to reduce energy consumption. But this reduces comfort and Is not precise, because the temperature of the water is unstable in the circulation system, while it can be lower than the minimum required temperature at the consumption point. Since the temperature of the domestic hot water at the outlet of the storage tank is higher than the temperature required at the individual consumption point during the timed circulation, costs increase. Since the consumption of hot water from the circulation system is also not taken into account, there is also an increase in the costs of circulation in the building.

A device for heating of domestic hot water Is known from patent document CZ 1991-605. This device for heating of domestic hot water makes up an additional part to the heating boiler, which is equipped with a boiler thermostat. A vertically arranged exchanger tank is connected to the heating boiler as well, which is internally equipped with a spirally arranged heat-carrying medium, connected in front of the heat-carrying medium outlet from the heating boiler and opening into its lower part. The heat exchanger tank is equipped with a utility water inlet in the lower part and a utility water outlet in the upper part.

From another patent document CZ 2010-672, a device for heating hot water in buildings with central water distribution is known, consisting of a first part made up of a storage tank with a supply of waste water from the building and the second part made up of a heat pump, a storage tank, and a control unit box, while an evaporator of the heat pump is arranged in the waste water storage tank and the heat pump is connected to the hot water insert arranged in the storage tank equipped with an electric heating insert, a cold water distribution pipe and a hot water supply pipe.

From the patent document JP20082411130, a design solution is known that solves the minimisation of the diversion of utility water before water of the required temperature starts flowing from the pipes. This design solution allows setting a requirement for a different utility water temperature at each consumption point, which means that if the water heating is central, the water temperature in the system must be approximately such as to meet the demand of the consumption point with the highest temperature. Hot and cold water is mixed at the output point. The disadvantage of this solution is that utility water must flow in the system, the temperature of which is higher than the required temperature of most consumption points. This, of course, means higher heat losses and therefore also higher energy consumption for domestic hot water.

From the above-mentioned state of the art, it is clear that the current state of the art has quite a number of disadvantages, with the biggest disadvantage of the known methods of water temperature regulation being that they are very energy- intensive, and due to the way they function, have large energy losses. The goal of the invention is to create an effective way of regulating water temperature, which will be cheap to manufacture, while enabling significant energy savings.

Principle of the Invention

The stated shortcomings are largely eliminated and the goals of the invention are fulfilled by a method of regulating the temperature of utility water circulating in the heating circulation of the central domestic hot water system to at least one consumption point, where the heating circulation system further contains a means for the circulation of utility water and a tank of utility water with a means for heating of domestic hot water, according to the invention, characterised by that at the last consumption point, or in its immediate vicinity, in the direction of flow of utility water through the heating circulation system, the utility water temperature is continuously measured by a utility water temperature gauge, connected to a control unit, with the rate of circulation of domestic hot water through the circulation system being regulated by the control unit, connected to the means for circulating of domestic hot water, so that the control unit controls the performance of the means for circulating of domestic hot water in such a way that the temperature of domestic hot water beyond the last consumption point has a constant temperature. The advantage is that it is possible to minimise losses on the reheating of domestic hot water, as known in the systems currently in use. Practically the same results are obtained when the temperature is measured in the immediate vicinity of the last consumption point, preferably as close as possible beyond it, in the direction of the flow of utility water through the heating circulation system. This solution enables implementation with minimal costs and with minimal interventions in the heating system, therefore it can also be used for additional implementation in existing systems. it is to advantage if the speed of circulation of heating utility water through the circulation system is changed by a control unit, by regulating the performance of the means for circulation of utility water, when the utility water temperature at the last consumption point drops or rises by more than 5% compared to the set constant temperature. The circulation speed will increase when the temperature of the utility water drops, and conversely, when the temperature rises, the circulation speed of the domestic hot water will decrease. The advantage is that due to the precise maintenance of the set temperature, losses are minimised, while the set temperature of the utility water at the consumption point is maintained. It is also to advantage that the losses in the return pipe are the lowest possible, regardless of the temperature of the water in the tank, and thus the losses in the supply pipe are also the lowest possible, because when the temperature in the tank increases, the temperature in the return pipe does not increase.

Furthermore, it is to advantage if the constant temperature of the utility water beyond the last consumption point is at least 40°C. This temperature is the lowest subjectively perceived as warm.

Furthermore, the stated shortcomings are largely eliminated and the goals of the invention are fulfilled by a heating circulation system of domestic hot water to at least one consumption point which further contains a means for circulating utility water and a tank of utility water with a means for heating utility water, for carrying out the above-mentioned method water temperature regulation, characterised by that, according to the invention, a domestic hot water temperature gauge is arranged at the last consumption point, or in its immediate vicinity, in the direction of the flow of utility water through the heating circulation system, which is connected to the control unit, which is connected to the means for domestic hot water circulation. The advantage of this arrangement is maintaining a constant temperature in the return pipe.

It is to advantage if the control unit is connected to the utility water temperature gauge in the utility water tank. The advantage is that it is possible to predict the consumption of heat at a time when there is no consumption, but the water in the pipes must be prepared for random consumption. It is then possible to determine whether the heat supply will last until the time when there is cheaper energy.

Furthermore, it is io advantage if the control unit is connected to a means for heating utility water. It is thus passible to simply monitor the amount of energy supplied to the system and subsequently determine the amount of energy required to be supplied to the system.

The main advantage of the invention is that, thanks to the control of the speed of the circulation according to the temperature at the last consumption paint, there will be significant savings in the energy consumed, as well as a reduction in the costs of the circulation of domestic htt water. At the same time, the cost of circulating utility water in the heating system will be reduced by up to 50%. The heating circulation system according to the invention can also adapt circulation to the need for a timed reserve so that the delivered amount of energy is exactly what is needed and is not higher due to the time differentiation of energy prices.

Overview of the Figures

The invention will be explained in closer detail with the help of drawings, in which fig. 1 schematically shows the connection of a heating system that has four consumption points, and fig. 2 schematically shows the connection of a heating system that has one consumption point.

Examples of the Performance of the Invention

Example 1

The heating circulation system 6 of the central heating system of circulating utility water (fig. 1) contains four consumption points 2, which are arranged on the circulation system 6 beyond the storage tank 4 of domestic hot water, which is a boiler, which contains a means 5 for the heating of utility water. On the circulating system 6, between the last consumption point 2.4 and the tank 4 of domestic hot water, a means 8 for circulating utility water is arranged. The tank 4 of domestic hot water contains an intake 10 of cold water.

At the last consumption point 2,4 in the direction of flow of utility water through the heating circulation system 6, a gauge 1. of the temperature of the domestic hot water is arranged, which is connected to a control unit 7, which is connected to the means 8 for the circulation of domestic hot water.

The control unit 7 is connected to the utility water temperature gauge 9 in the utility water tank 4.

The control unit 7 is further connected to the means 5 for heating utility water.

According to the method of regulating the temperature of the utility water circulating in the above-mentioned heating circulation system 6 of the central domestic hot water system, at the last consumption point 2,4, in the direction of the service water flow through the heating circulation system 6, the utility water temperature is continuously measured by the utility water temperature gauge 1 with the rate of circulation of utility water through the circulation system 6 being regulated so that the temperature of utility water beyond the last consumption point 2n has a constant temperature of 40°C.

The circulation speed of the domestic hot water through the circulation system 6 changes when the service water temperature drops or rises at the last consumption point 2.4 by more than 5% compared to the set constant temperature, while the circulation speed increases when the utility water temperature drops and, conversely, when the temperature rises, the speed the circulation of the domestic hot water will decrease.

The heating circulation system 6 works practically in such a way that the circulation runs continuously and the temperature of the utility water at the last consumption point 2.4 is continuously measured, while if the temperature exceeds a temperature of 40°C by 5%, the circulation slows down or stops. If the water temperature drops by 5% below 40°C, the circulation will speed up.

The above-mentioned design solution of the heating circulation system 6 and the method of regulating the temperature of the utility water circulating in this heating circulation system 6 reduces the energy requirement for circulation operation as follows:

Savings calculation for DN20 pipes:

Standard 55°C U = 0.18W/m2K

40°C U = 0.174W/m2K

30°C U = 0.172W/m2K

Savings calculation for DN40 pipes:

Standard 55°C U = 0.27W/m2K

40°C U = 0.262W/m2K

30°C U = 0.258W/m2K

Loss in DN20 pipes

Q = U . I. (tpotr - tint)

Q55 = 0.18.1 .(55-20) = 6.3W/m

Q40 = 0.174.1.(40-20) = 3.48W/m

Q30 = 0.18.1 .(30-20) = 1.72W/m Loss in a DN40 pipes

Q = U . I. (tpotr - tint)

Q55 = 0.27.1.(55-20) = 9,45W/m

Q40 = 0.262.1.(40-20) = 5.24W/m

Q30 = 0.258.1.(30-20) = 2.58W/m

If the temperature in the pipes is 55°C in 1/3 of the length, 40°C in the other 1/3 and

30°C in the other 1/3, the total savings will be:

Q55 = 0.27.1 .(55-20) = 9.45W7m 9.45-9.45 = 0w/m

Q40 = 0.262.1.(40-20) = 5.24W/m 9.45-5.24 = 4,21 w/m

Q30 = 0,258.1.(30-20) = 2.58W/m 9.45-2.58 = 6.87w/m

This results in a savings of 11 ,08w/m, which is 40% less.

For a house that needs 1000l per day: annual costs for domestic hot water heating according to the standard: 15,975 kWh annual costs for domestic hot water heating with circulation according to the standard:25,560 kWh annual cost of domestic hot water heating with circulation using the invention:

21,726kWh

This saving is achieved only by changing the regulation, that is at almost no cost. For the given house, at an energy price of CZK 8 per 1 kWh, the invention represents a savings of CZK 30,600/year.

Example 2

The heating circulation system 6 of the central heating system of circulating utility water (fig. 2) contains one consumption point 2, which is arranged on the circulation system 6 beyond the tank 4 of domestic hot water, which is a boiler, which contains a means 5 for heating utility water. On the circulating system 6, between the only and therefore also the last consumption point 2 and the storage tank 4 of domestic hot water a means 8 for the circulation of utility water is arranged. The tank 4 of domestic hot water contains an intake 10 of cold water. At this last consumption point 2 in the direction of the flow of utility water through the heating circulation system 6, a gauge 1 of the temperature of the domestic hot water is arranged, which is connected to the control unit 7, which is connected to the means 8 for the circulation of domestic hot water.

The control unit 7 is connected to the utility water temperature gauge 9 in the utility water tank 4.

The control unit 7 is further connected to the means 5 for heating utility water.

According to the method of regulating the temperature of the utility water circulating in the above-mentioned heating circulation system 6 of the central domestic hot water system, at the last consumption point 2, in the direction of the utility water flow through the heating circulation system 6, the utility water temperature Is continuously measured by the utility water temperature gauge 1 with the rate of circulation of utility water through the circulation system 6 being regulated so that the temperature of utility water beyond the last consumption point 2 has a constant temperature of 45°C.

The circulation speed of the domestic hot water through the circulation system 6 changes when the utility water temperature drops or rises at the last consumption point 2 by more than 5% compared to the set constant temperature, while the circulation speed increases when ths utility water temperature drops and, conversely, when the temperature rises, the circulation speed the circulation of the domestic hot water will decrease.

Industrial Application

The method of regulating water temperature and the heating system, according to the invention, can be used to regulate the temperature of utility water, in family as well as residential and industrial buildings. List of Reference Marks

1 utility water temperature gauge

2,1,2,2,.., consumption point

2n last consumption point

4 utility water tank

5 means for heating utility water

6 heating circulation system

7 control unit

8 means for the circulating of utility water

9 utility water temperature gauge in the utility water tank

10 cold water intake