Method for adjusting the setpoint temperature of a heat transfer medium

Abstract

A method for adjusting the setpoint temperature of a heat transfer medium circulating in a heating or cooling system (9) inside a building or at least inside a surrounding part of a building. The heating or cooling circuit includes a plurality of heat transferring units, each with a temperature controlled valve. A sum opening degree (OD) of all temperature controlled valves is determined in a time dependent manner and a setpoint temperature T.sub.w,ref of heat transferring medium is controlled according to a predetermined sum opening degree (OD) of all temperature controlled valves. A heating system (9) is provided for supplying heat to a building or a part of the building via a liquid heat transfer medium circulated in a circuit. The heating system (9) includes heat transferring units, each being equipped with a temperature controlled valve. The system is controllable according to the method for adjusting the setpoint temperature.

Claims

1. A method for adjusting a setpoint temperature of a heat transfer medium circulating in a heating or cooling system inside a building or circulating in a heating or cooling system at least inside a surrounding part of a building, the method comprising the steps of: providing a heating or cooling circuit comprising a plurality of heat transferring units, each of the plurality of heat transferring units being equipped with a temperature controlled valve; determining a sum opening degree of all temperature controlled valves in a time dependent manner; and controlling the setpoint temperature of heat transferring medium according to a predetermined sum opening degree of all temperature controlled valves, the time dependent sum valve opening degree being based on an actual estimated hydraulic system resistance compared with an estimated minimum and/or maximum hydraulic system resistance, the estimation of the minimum and/or maximum hydraulic system resistance being based on estimated hydraulic systems resistances registered in the last 5 to 25 days, wherein the estimation of the minimum and/or the maximum hydraulic system resistance is provided by filtering peak values of a continuously determined hydraulic system resistance, wherein the sum opening degree of all temperature controlled valves is determined on the basis of at least one of a volume rate of flow and a pressure head through the heating or cooling circuit.

2. A method according to claim 1, wherein the setpoint temperature is also adjusted according to an outside temperature outside of the building.

3. A method according to claim 1, wherein the sum opening degree of all temperature controlled valves is determined from at least one of sensor based data and electrical data of a heating or cooling system pump.

4. A method according to claim 1, wherein the method provides a first phase when the minimum and maximum hydraulic system resistance are estimated and a second phase when the sum opening degree of all temperature controlled valves is determined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a view showing a normal control structure of a heat pump according to prior art;

(2) FIG. 2 is a view showing an overview of the control system for carrying out the method according to an embodiment of the present invention;

(3) FIG. 3 is a view showing a control structure for a heat pump of a heating system according to the present invention;

(4) FIG. 4 is a view showing a control structure for a heat pump of a heating system according to still another embodiment of the present invention;

(5) FIG. 5 is a view showing a control structure for a heat pump of a heating system according to still another embodiment of the present invention; and

(6) FIG. 6 is a diagrammatic view showing an adaptation of a heat curve according to the need of the heating system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) Referring to the drawings in particular, FIG. 1 shows a normal control structure of a heat pump 1 which may be implemented in a single-family house, according to prior art. The outside temperature T.sub.out is mapped to a setpoint for the water temperature T.sub.w,ref by the heat curve, and the compressor 2 is adjusted such that the water temperature T.sub.w reaches the setpoint and a room temperature T.sub.r is achieved when the heating system 3 is operated. However, according to this implementation, the user has to manually adjust the heat curve to achieve the desired room temperature as the shape of the curve depends amongst other things on the type of heating system used and on the insulation of the house.

(8) FIG. 2 shows an overview of a control system for carrying out the method according to an embodiment of the present invention. The embodiment shown in FIG. 2 illustrates the basic principle of a control system for carrying out the inventive method. The water temperature setpoint T.sub.w,ref, which is supplied to the heat pump 6 of the heating system, is calculated based on the outside temperature T.sub.out measured, for example, by a temperature sensor placed outside the building, and the opening degree OD of the heating system is estimated by an opening degree estimation means 4. Specifically, the opening degree is calculated based on estimations of the flow Q and the head H which are input to the opening degree estimation means 4. Both values, the opening degree OD and the outside temperature T.sub.out are then used as input for adapting the adaptive heat curve 5. The heat curve 5 is thus automatically adapted to the need of the heating system.

(9) FIG. 3 shows a control structure for a heat pump 6 of a heating system 9 according to the invention. In this case, the output from a regulator 7 uses a reference opening degree OD.sub.ref and an opening degree OD from an opening degree estimation means 4 arranged in a feedback loop to output the water temperature setpoint T.sub.w,ref. The water temperature setpoint T.sub.w,ref then is fed to a compressor control 8 of the heat pump 6 which in turn outputs a water temperature value T.sub.w to the heating system 9.

(10) FIG. 4 shows a control structure for a heat pump 6 of a heating system 9 according to another embodiment of the present invention. According to this embodiment, feedback from the entire heating system 9 is used for the automatic adaptation of the heat curve 5 wherein Q indicates the measurement or the estimation of the flow, and H indicates the measurement or the estimation of the head of the system in order to calculate or estimate the opening degree OD of the radiators in an OD estimation means 4.

(11) FIG. 5 shows a control structure for a heat pump 6 of a heating system 9 according to still another embodiment of the present invention. This again is a heat pump control structure with feedback from the entire heating system. The pump 10 provides an alternate temperature T.sub.out to the heat pump 6. The heat pump 6 uses the alternate temperature T.sub.out as input for the heat pump heat curve 5.

(12) Both embodiments which are illustrated in FIG. 4 and FIG. 5 provide a short term adaptation to the heat demand. Sudden changes in temperature due, e.g., to free heat causes the radiator valves to change the opening degree OD. This, in turn, causes changes in the flow and head which is detected and used to correct the water temperature reference T.sub.w,ref with the correction temperature T.sub.out. With the correction temperature there is also provided the ability to carry out a long term adaption to the house or building. The heat curve according to the current outside temperature T.sub.out is adjusted to the current water temperature setpoint. T.sub.w,ref thereby, the heat curve is adjusted to the house or building over time. This eliminates unnecessary high water temperatures, and provides the required heating energy with an optimal COP.

(13) FIG. 6 shows a diagrammatic view of the adaptation of a heat curve according to the need of the heating system whereby the heat curve at startup, the heat curve after a year, and the heat curve every 4 weeks is displayed. The heat curve is automatically adapted to the need of the heating system. The heat curve adapts to the heat demand of the house according to the current outside temperature throughout the whole year.

(14) The above described embodiments of the invention can be used in heating systems with changing media temperatures. The control system also works with heating systems with floor heating instead of radiators as the floor heating system provides the same feedback of the room temperatures. Further, the control system is not limited to heat pumps, but also may be implemented in other types of heating or cooling devices.

(15) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

APPENDIX

List of Reference Numerals

(16) 1 heat pump according to prior art

(17) 2 compressor according to prior art

(18) 3 heating system according to prior art

(19) 4 opening degree estimation means

(20) 5 heat curve

(21) 6 heat pump

(22) 7 regulator

(23) 8 compressor control

(24) 9 heating system

(25) 10 pump