DESCRIPTION

[001] The invention relates to indoor microclimate control systems for providing heating, hot water supply and free cooling using sewage or wastewater potential, and to methods of controlling such indoor microclimate control systems.

[002] Various heating and cooling systems are known for buildings, where in most cases the heating and cooling function is provided by unrelated systems. Such systems are disclosed in the international patent application publication No. WO2015/007293, in the US patent application publication No. US2012/159980, German patent application publications Nos. DE102010006882 and DE2438622, and European patent application publication No. EP2148143. As a result of these prior art systems, their operation and management are complex and not always coordinated. Attempts have also been made to design systems that combine heating and cooling functions, but they are also complex and do not always provide the installed energy efficiency. Accordingly, the object of the invention is to provide an efficient and simple heating and cooling system.

[003] The object of the invention is achieved by creating an indoor microclimate control system comprising a wastewater accumulation tank in synergy with heating and free cooling systems. More precise heat and colling control is provided. The system comprises a sewage or wastewater solids separation tank for the separation of thick a sewage or wastewater fractions connected to a wastewater accumulation tank. In addition, the system comprises a wastewater inlet connected to the sewage or the wastewater particulate separation tank in such a way that the incoming wastewater through the wastewater particulate separation tank can enter the wastewater storage tank. In turn, a heating heat exchanger circuit and a free-cooling heat exchanger circuit are placed in the wastewater storage tank. The free-cooling heat exchanger circuit is located below the heating heat exchanger circuit.

[004] To control the system, the system includes an inlet wastewater control valve connected to the wastewater inlet and configured for inlet wastewater control. The first heat exchanger circuit flow valve is connected to the heating exchanger circuit, configured to change the heating surface area of the heating exchanger circuit. In addition, a second heat exchanger circuit flow valve may be connected to the heat exchanger circuit, configured to additionally change the heating surface area of the heat exchanger circuit. The system further includes a free-cooling heat exchanger circuit flow valve connected to the free-cooling heat exchanger circuit and configured to change the cooling surface area of the free-cooling heat exchanger circuit. The system also contains several sensors. An inlet effluent thermometer located in the effluent inlet or effluent particulate separation tank and configured to determine the incoming effluent temperature. A heat exchanger circuit thermometer located near the heating exchanger circuit and configured to determine the temperature in the area of the heating exchanger circuit. Free-cooling heat exchanger circuit thermometer located near the free-cooling heat exchanger circuit and configured to determine the temperature in the free-cooling heat exchanger circuit area. An inflow meter connected to the inflow and configured to record the inflow volume. Heat exchanger circuit heat meter connected to the heating heat exchanger circuit and configured for instantaneous heat demand accounting. Free-cooling heat exchanger circuit heat meter connected to the free-cooling heat exchanger circuit and configured for cooling instantaneous demand accounting.

[005] In addition, the system comprises a control unit connected to the above-mentioned thermometers for receiving temperature reading data from the respective system units and to the incoming wastewater meter for receiving incoming wastewater volume reading data and to the above-mentioned meters for receiving instantaneous heat demand data. The control unit is also connected to valves for their control based on the data received from said thermometers and meters.

[006] The indoor microclimate control system further comprises a sewage pump well located between the sewage supply and the sewage inlet for the sewage supply to the sewage inlet.

[007] In addition, the indoor microclimate control system further comprises a thick fraction pressure line having a pump configured to discharge the separated thick fraction to the wastewater collection system at an end located in the wastewater particulate separation tank.

[008] The system further comprises a pressure cooling tank connected to the wastewater accumulation tank and a wastewater solids separation tank for receiving the thick fraction separated therein, thus ensuring a decrease in the wastewater pressure. [009] In addition, a new method for controlling the indoor microclimate control system was developed. The method for control includes the following steps: a) receiving the instantaneous cooling demand value (QFREE) in Joules (J) at the control unit from the free-cooling heat exchanger circuit heat meter and/or receiving the instantaneous heat demand value (QHEAT) in Joules (J) at the control unit from the heating heat exchanger circuit; b) opening the incoming sewage control valve if the instantaneous cooling demand value (QFREE) is less than the instantaneous heat demand value (QHEAT) and closing the incoming sewage control valve if the instantaneous cooling demand value (QFREE) is equal to or greater than the instantaneous heat demand value (QHEAT); c) setting the upper temperature threshold (TH 16) and the lowest temperature threshold (TL16) for the temperature values incoming from the free-cooling heat exchanger circuit thermometer, wherein the upper temperature threshold (TH 16) being the highest temperature value in summer above which the system must not raise the sewage temperature in the sewage storage tank, and wherein the lowest temperature threshold (TL16) is the lowest temperature in winter below which the system must not reduce the sewage temperature in the sewage storage tank; d) setting of the heating mode; or e) setting of the cooling mode.

[010] The lowest and highest wastewater temperatures must be set in the control unit before returning to the city wastewater networks (hereinafter - discharge temperature), this temperature will be indicated by the free-cooling heat exchanger circuit thermometer. These temperatures serve as a criterion for determining the condition of the system and determine the operating temperature corridor of the installation, i.e. the lowest discharge temperature in winter below which the system must not cool the effluent and the highest discharge temperature in summer above which the system must not raise the effluent temperature before discharge. In temperate climates, the optimal temperature distribution corridor is 7 °C - 18 °C to meet the heating needs in winter and the indoor cooling needs in summer. When operating in heating mode, the heat recovery potential will be limited at this temperature, the lower the set temperature, the higher the heat recovery potential and vice versa.

[011] In addition, the upper temperature threshold (TH 16) is the highest temperature in summer above which the system must not raise the effluent temperature in the effluent storage tank, and in addition the lower temperature threshold (TL16) is the lowest temperature in winter below which the system must not reduce the effluent temperature in the effluent storage tank. To ensure favorable, comfortable conditions for the occupants of the building, the highest temperature threshold (TH 16) should then be set to 18 °C (29 IK) and the lowest temperature threshold (TL16) to be set to 7°C (280K).

[012] Upon receipt of the data, the control unit calculates the total heat balance, knowing the instantaneous heat demand from the heat exchanger circuit heat meter and the free-cooling heat exchanger circuit heat meter. Before reporting the opening of the sewage inlet valve to the control unit, the instantaneous state of the system must be determined by determining the heat potential generated by the free cooling mode detected by the heat meter in the free cooling heat exchanger circuit. If the free heat exchanger circuit heat meter value - heating heat exchanger circuit heat meter value <0, then the control unit calculates according to equation (40) and instructs to open the wastewater inlet valve, supplying wastewater flow from the city to the free cooling heat exchanger circuit heat meter value - heat circuit heat meter value + incoming wastewater meter value >= 0 and the system equilibrium state has been reached to compensate for the lack of heat in the system. The data from the measuring devices to the control unit is preferably updated once a minute, each time data is received from the devices. However, the data recovery time can be shortened or extended if necessary. The control unit records the state of the system, thus determining the direction of heat flow, for example, a situation where wastewater in the tank approaches the discharge temperature, but after recording the system state, the heat flow from free cooling exceeds does not yet command the sewage inlet valve to open, as heat is expected to increase in the tank and no urban sewage heat potential is required.

[013] Setting of the heating mode involves determining the instantaneous heat demand value (QHEAT) in the control unit according to the following equation:

QHEAT = QFREE + ((T14 - T16) * c * M) [J], (40) where

QFREE is the instantaneous heat demand value (QFREE) [J],

M - amount of incoming sewage [kg/s] accounted by the incoming sewage meter (17), c - calorific value [J/kg*K],

T16 - temperature value [K] accounted by the free-cooling heat exchanger circuit thermometer, T14 - temperature value [K] accounted by the incoming sewage thermometer, Wherein in the heating mode, if the temperature value (T16) approaches the lowest temperature threshold (TL16), the control unit determines the QHEAT value according to equation (40) and if the determined QHEAT value is not equal to QFREE value, the control unit sends a signal to the incoming sewage control valve to open it, and the incoming sewage control valve is closed after recalculated QHEAT value is equal to QFREE value.

[014] The same setting of the heating mode may be accomplished by control of amount on the incoming sewage. Setting of the heating mode involves determining the amount of the incoming sewage to be supplied to the sewage storage tank according to the following equation: M=(QHEAT - QFREE)/(T14 - T16) * c [kg/s], (41) wherein in the heating mode, if the temperature value (T16) approaches the lowest temperature threshold (TL16), then the control unit determines the QHEAT value and if the determined QHEAT value is not equal to QFREE value, then the control unit calculates the amount of the incoming sewage according to equation to compensate an amount of already transferred heat energy and the control unit sends a signal to the incoming sewage control valve to open it, and the incoming sewage control valve is closed after the calculated amount of the incoming sewage is supplied into the sewage storage tank and a temperature (T16) pre-set in the control unit is reached

[015] Accordingly, if the value on the free-cooling heat exchanger circuit thermometer approaches a lower set temperature during the heating period, the control unit calculates according to equation (40) and if the QHEAT value is not equal to QFREE, a command is sent to the control unit to open the sewage inlet valve from a network with a higher heat potential until the conditions of equation (40) are met. As the wastewater potential in the tank increases and the heat demand in the building decreases, the control unit reads it from the flow and temperature graph values of the heat exchanger circuit, successively sending a command to close the wastewater inlet valve because the system is in balance.

[016] Setting of the cooling mode involves determining the instantaneous cooling demand value (QFREE) in the control unit according to the following equation:

QFREE = QHEAT + ((T16 - T14) * c * M) [J], (50) where QHEAT is instantaneous heat demand value (QHEAT) [J],

M - amount of incoming sewage [kg/s] accounted by the incoming sewage meter, c - calorific value [J/kg*K],

T16 - temperature value [K] accounted by the free-cooling heat exchanger circuit thermometer, T14 - temperature value [K] accounted by the incoming sewage thermometer.

[017] The same setting of the cooling mode may be accomplished by control of amount on the incoming sewage. Setting of the cooling mode involves determining the amount of the incoming sewage to be supplied to the sewage storage tank according to the following equation:

M=(QFREE - QHEAT)/(T16 - T14) * c [kg/s], (51) wherein in the cooling mode, if the temperature value (T16) approaches the highest temperature threshold (TH 16) and the instantaneous cooling demand value (QFREE) is bigger than the instantaneous heat demand value (QHEAT), the control unit calculates the amount of the incoming sewage (M) according to equation (51) to compensate an amount of already supplied heat energy and the control unit and opens the incoming sewage control valve and closes the incoming sewage control valve after the calculated amount of the incoming sewage (M) is supplied into the sewage storage tank and a temperature (T16) pre-set in the control unit is reached. .

[018] Wherein in the cooling mode, if the temperature value (T16) approaches the highest temperature threshold (TH 16) and the instantaneous cooling demand value (QFREE) is bigger than the instantaneous heat demand value (QHEAT), the control unit determines the QFREE value according to equation (50) to open the incoming sewage control valve and to close it after fulfilling the conditions of equation (50).

[019] The upper temperature of the wastewater is set in the system control unit before the wastewater is discharged from the tank, respectively, if the free cooling mode heats the wastewater to the upper temperature. As the wastewater in the tank approaches the upper temperature, the control unit analyzes the data from the circuit thermometers. Respectively, under the condition when a temperature rise in the tank at the free cooling circuit at the upper outlet temperature is observed, the system state is recorded and at the condition when the free cooling circuit heat meter value - heating heat exchanger circuit heat meter value > 0, the control unit performs the equation (50) and instructs to open the wastewater valve by supplying city wastewater in the calculated amount until the wastewater temperature in the tank is properly reduced and the following condition is met: free heat exchanger circuit heat meter value - heating heat exchanger circuit heat meter value =<0, system equilibrium state has been reached.

[020] During the summer, the upper limit of the setting operates, providing a corresponding free cooling mode for indoor cooling, the control unit reads the value on the free cooling heat exchanger circuit thermometer, if it approaches the upper temperature limit, then the control unit is sent to open the sewage valve and supply heat potential until the conditions of equation (50) are met. When the wastewater potential in the tank decreases and the indoor cooling demand in the building decreases, the control unit reads it from the flow and temperature graph values of the free cooling heat exchanger circuit, successively sending a command to close the sewage valve because the system is in balance.

[021] The object of the invention can be used in the energy supply of a building, wherein it is possible to provide heating, hot water and indoor cooling of the building in the so-called free cooling mode. The device is especially efficient for installation in the city's centralized sewage networks, because here the volume and temperature of sewage is constant throughout the year. The volume of wastewater is higher in the winter months, but the temperature decreases (8- 10°C), in the summer months the volume of wastewater decreases slightly, but its temperature increases (14-16°C). The unit is designed to use urban wastewater only to the extent necessary to ensure the installed heating and cooling parameters. This means that in cases where the heat demand of the building coincides with the demand for indoor cooling, wastewater from the city network is not used at all.

[022] In the summer months, at higher indoor cooling demand, the wastewater in the tank heats up, if there is a constant heat demand in the building, such as hot water, then a heat pump will turn on, cooling the wastewater in the tank, urban wastewater to maintain the installed indoor cooling mode. As the tank temperature rises, as the tank will not cool down sufficiently for heating purposes through the heat pump circuit, the sewage pump will switch on and supply wastewater from the city sewage network at a lower temperature, ensuring indoor cooling demand. In this case, the wastewater will be discharged back to the city network at a higher temperature, which does not interfere with its treatment in the wastewater treatment plant. In cooling mode, on the other hand, a variant is possible when peak loads are cooled by compressor equipment.

[023] During the winter months, in buildings with 0 energy consumption, there is a regular demand for indoor cooling (similar to production rooms, server rooms, etc.), the southern facades heat up, the northern cools down. This means that when heat is removed from the room, it is transferred to the sewage tank through a free cooling circuit, where the heat pump circuit is used for heating purposes. Therefore, the plant does not depend entirely on urban wastewater networks for heat production, they cover the difference not provided by the free cooling mode, minimizing the potential for heat removed from urban wastewater, and in some cases even increasing it. This, in turn, does not increase the load on wastewater treatment plants and creates cheap, energy efficient and green energy.

[024] The control unit regulates the flow control valves based on the instantaneous heat demand and the heat potential in the wastewater storage tank. The heat potential in the tank is measured depending on the sewage supply and temperature. Sewer heat exchanger circuits are separated by flow valves to reduce hydraulic resistance. The first heating heat exchanger circuit is located at the top of the tank and is always open, subsequent circuits are opened as required to increase the capacity of the wastewater heat exchanger depending on the heat pump demand. Identical to the free cooling circuit. The circuits are arranged according to the direction of the heat gradient in the tank, the lowest temperature in the lower part, the highest temperature in the upper part. Tanks shall be calculated with a margin to ensure a more even heat exchange as well as to reduce the impact of potential network failure risks on system operation. The system control unit takes into account the wastewater outlet temperature, preventing it from falling below the set temperature. The system is set to the potential for changes in the wastewater temperature, the difference of which is measured at the inlet of the wastewater solids separation tank and at the outlet to the city networks. This difference can be changed depending on the wastewater temperature and the required wastewater heat potential with the seasons. The lower the difference, the more often the amount of wastewater in the tank needs to be changed. This allows the system to balance and reduce the effects of winter and summer peak loads.

[025] In free cooling mode, the control unit controls the flow valve of the free cooling heat exchanger identically. If the set temperature difference is not ensured, the flow valve of the free-cooling heat exchanger circuit is opened, thus increasing the flow and heat dissipation area in the sewage tank. In the control unit, the opening / closing of the free-flow heat exchanger circuit flow valve is set when the flow values change, these values can be changed in the system.

[026] The object of the invention is explained in more detail through the following examples of its implementation.

[027] Fig. 1 is the basic scheme of the indoor microclimate control system.

[028] Fig. 2 is a schematic diagram of an indoor microclimate control system, supplemented by an illustration of the control unit (20) and related elements.

[029] Fig. 3 is a graph showing the potential of wastewater networks in kWh at the amount of wastewater available at a particular stage depending on the set wastewater cooling limit (t° - IK).

[030] Fig. 4 is an overall scheme of one embodiment of the indoor microclimate control system.

[031] Figs. 1 and 2 illustrates one embodiment of the invention. An indoor microclimate control system comprising a wastewater storage tank (1), a wastewater solids separation tank (2) for separating thick wastewater fractions connected to said wastewater storage tank (1). The wastewater particulate separation tank (2) is connected to the wastewater inlet (3) in such a way that the incoming wastewater through the wastewater particulate separation tank (2) can enter the wastewater storage tank (1). In addition, the wastewater inlet (3) includes an inlet wastewater inlet valve (10) configured to control the inlet wastewater. In addition to the wastewater inlet (3), there is an inlet wastewater thermometer (14) configured to determine the inlet wastewater temperature (see Fig. 1). In turn, Fig. 2 shows an embodiment of the invention when the wastewater thermometer (14) is placed in the wastewater solids separation tank (2). Before the sewage inlet (3), there is a sewage pump well (30), which in turn is connected to the sewage supply (31). In turn, a heating heat exchanger circuit (7) with a heating inlet (4) and a free-cooling heat exchanger circuit (9) with a free-cooling inlet (5) are placed in the wastewater storage tank (1). In addition, the free-cooling heat exchanger circuit (9) is located below the heating heat exchanger circuit (7) closer to the base of the tank (1). The heating heat exchanger circuit (7) is connected to a first heating heat exchanger circuit flow valve (11) configured to change the heating surface area of the heating heat exchanger circuit (7). In addition, the heating heat exchanger circuit (7) is connected to a second heating heat exchanger circuit flow valve (12), which is configured to additionally change the heating surface area of the heating heat exchanger circuit (7). In turn, the free-cooling heat exchanger circuit (9) is a free-cooling heat exchanger circuit flow valve (13) configured to change the cooling surface area of the free-cooling heat exchanger circuit (9).

[032] In addition, the system contains sensor elements for obtaining the data required for system control. The system comprises a heating heat exchanger circuit thermometer (15) located in the vicinity of the heating heat exchanger circuit (7) and configured to determine the temperature in the zone of the heating heat exchanger circuit (7) and a free cooling heat exchanger circuit thermometer (16) located in the free cooling heat exchanger circuit (9). nearby and configured to determine the temperature in the zone of the free cooling heat exchanger circuit (9). The system further comprises an incoming wastewater meter (17) connected to the wastewater inlet (3) and configured to account for the volume of incoming wastewater. The system also comprises a heat exchanger circuit heat meter (18) connected to the heating heat exchanger circuit (7) and configured for instantaneous heat demand accounting, and a free cooling heat exchanger circuit heat meter (19) connected to the free cooling heat exchanger circuit (9) and configured for cooling, for the accounting of current demand. To provide system control, the system includes a control unit (20) configured to control the system. The control unit (20) is connected to thermometers (13, 14, 15) for receiving temperature reading data and to an incoming wastewater meter (17) for receiving incoming wastewater volume reading data, and to meters (18; 19) for receiving instantaneous heat demand data, and with valves (5; 10; 11; 12; 13) for controlling them based on data received from thermometers (13, 14, 15) and meters (17; 18; 19). See Figs. 1 and 2.

[033] The indoor microclimate control system further includes a thick fraction pressure line (32) having a pump (35) configured to discharge the separated thick fraction to the wastewater collection system (33) at an end located in the wastewater particulate separation tank (2). The system further comprises a pressure cooling tank (34) connected to the wastewater accumulation tank (1) and a wastewater solids separation tank (2) for receiving the thick fraction separated therein, thus ensuring a reduction of the wastewater pressure. See Figs. 1 and 2. [034] Fig. 3 illustrates the potential of the wastewater network in kWh, where the system is set to 1.5°C (274.5K) difference between the inlet and outlet wastewater temperature. As shown in the example, the heating demand is partially covered by the heat generated by free cooling in the tank. In the specific section of the wastewater supply network, 530 m3/day are available per day, in such a scenario, only 44 m3 of wastewater per day is required to ensure the operation of the system.

[035] Fig. 4 illustrates an overall system of indoor microclimate control. The system comprises a wastewater storage tank (1) as described in embodiments of Figs. 1 and 2. The wastewater storage tank is connected to a city sewage network (60). The wastewater storage tank (1) is also connected to a building sanitary equipment (61) via the heating heat exchanger circuit (7). The building sanitary equipment (61) is further connected to a hot water system of a building (63). The wastewater storage tank (1) is also connected to a heat exchanger (65) and to a heat pump (65) via the heating heat exchanger circuit (7). The wastewater storage tank (1) is further connected to a building climate control system (62) via the free-cooling heat exchanger circuit (9). The building climate control system (62) further includes a flow control valve (67) in order to manage a flow from the building climate control system (62) to the free-cooling heat exchanger circuit (9) and the heat exchanger (66). The system further comprises multiple pumps (69) for providing a water flow or other liquid media flow within the system is necessary direction of the flow (72). The Fig. 4 also discloses temperature ranges which system provides and controls during its operation. The system further comprises an accumulation tank (64) connected to the hot water system of a building (63) and to the heat pump (65). The accumulation tank (64) is necessary for keeping constant temperatures within the hot water system of a building (63) and within the heat pump (65) - the temperatures are disclosed in Fig. 4. The accumulation tank (64) itself is connect to an inflow from a heating unit (70), to an outflow to a heating unit (71) and to an inflow from a water pipe (68).

[036] While the invention may be susceptible to various modifications and alternative forms, specific embodiments of which have been shown by way of example in the figures and have been described in detail herein, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention includes all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the following claims. [037] List of references

1 - a sewage storage tank;

2 - a sewage particulate separation tank;

3 - a sewage inlet;

4 - a heating inlet;

5 - a free-cooling inlet;

7 - a heating heat exchanger circuit;

9 - a free-cooling heat exchanger circuit;

10 - an incoming sewage control valve;

11 - a first heating heat exchanger circuit flow valve;

12 - a second heating heat exchanger circuit flow valve;

13 - a free-cooling heat exchanger circuit flow valve;

14 - an incoming sewage thermometer;

15 - a heating heat exchanger circuit thermometer;

16 - a free-cooling heat exchanger circuit thermometer;

17 - a incoming sewage meter;

18 - a heating heat exchanger circuit heat meter;

19 - a free-cooling heat exchanger circuit heat meter;

20 - a control unit;

30 - a sewage pump well;

31 - a sewage supply;

32 - a thick fraction pressure line;

33 - a wastewater collection system;

34 - a pressure reduction tank;

35 - a pump;

40 - an equation for determining the instantaneous heat demand value;

41 - an equation for determining the amount of the incoming sewage to be supplied to the sewage storage tank;

50 - an equation for determining the value of the instantaneous cooling demand;

51 - an equation for determining the amount of the incoming sewage to be supplied to the sewage storage tank;

60 - city sewerage network;

61 - building sanitary equipment; 62 - building climate control system;

63 - a hot water system of a building;

64 - an accumulation tank;

65 - a heat pump;

66 - a heat exchanger;

67 - a flow control valve;

68 - an inflow from a water pipe;

69 - a pump;

70 - inflow from a heating unit;

71 - outflow to a heating unit;

72 - direction of a flow;

QFREE - an instantaneous cooling demand value [J] ;

QHEAT - an instantaneous heat demand value [J],

M - amount of incoming sewage [kg/s] ; c - calorific value [J / kg * K];

T16 - temperature value [K] counted by free-cooling heat exchanger circuit thermometer;

T14 - temperature value [K] counted by the incoming sewage thermometer;

TL16 - the lowest temperature threshold; and

TH 16 - the highest temperature threshold.