Search

EP-3879189-B1 - HEATING SYSTEM

EP3879189B1EP 3879189 B1EP3879189 B1EP 3879189B1EP-3879189-B1

Inventors

  • Hargassner, Markus

Dates

Publication Date
20260513
Application Date
20210301

Claims (5)

  1. Heating system comprising a heat source (1), a consumer (4), and a heating circuit connected to the heat source (1) and to the consumer (4), having a circulation pump (6), the flow line (2) and the return line (3) of which heating circuit being connected to one another by a bypass (5), and comprising a control device (10) for actuating the circulation pump (6) as a function of the heating circuit temperature, wherein the heating circuit has a valve (9), characterized in that the valve (9) is a switching valve (9) opening at an applied minimum pressure difference, which can be subjected, with the aid of the circulation pump (6), to a pressure difference which lies above or below the minimum pressure difference as a function of the heating circuit temperature.
  2. Heating system according to claim 1, characterized in that the switching valve (9) is arranged in the return line (3) upstream of the bypass (5), and in that the control device (10) actuates the circulation pump (6), provided in the return line (3) downstream of the bypass (5), as a function of the return line temperature.
  3. Heating system according to claim 1, characterized in that the switching valve (9) is arranged in the return line (3) downstream of the bypass (5), and in that the control device (10) actuates the circulation pump (6), provided in the heating circuit section (8) on the side of the bypass (5) facing the consumer (4), as a function of the flow line temperature.
  4. Heating system according to one of claims 1 to 3, characterized in that the bypass (5) has a switching valve (12) closing at an applied minimum pressure difference.
  5. Heating system according to one of claims 1 to 4, characterized in that the rotational speed of the circulation pump (6) is controllable.

Description

The invention relates to a heating system with a heat circuit connected to a heat source and a consumer, comprising a circulation pump, the flow and return of which are connected to each other by a bypass, and with a control device for controlling the circulation pump depending on the heat circuit temperature. From the EP2 275 748 A2 A heating system is known that includes a boiler and a heat storage tank connected to the boiler via a flow and return line. A charging pump is provided in the return line to charge the heat storage tank; its speed and power can be controlled depending on the flow temperature. To operate the boiler at its optimum efficiency, a return temperature within a predetermined range must be maintained. For temperature control, the return line is connected to the flow line via a bypass, allowing heated heat transfer fluid to be fed into the return line from the flow line as needed. For this purpose, the bypass is connected to the return line using a three-way valve. The three-way valve is controlled based on the return temperature. A differential pressure control valve is also located downstream of the three-way valve in the return line. This valve ensures a constant pressure drop that is as independent as possible from the flow rate, but it does not influence the control of the bypass. A disadvantage is the increased design complexity resulting from the three-way valve and its control system. In a heating circuit with parallel-connected radiators connected to a flow and a return pipe, it is known ( DE 10 2009 007 053 A1 ), to connect the flow and return via a pressure-controlled bypass valve in order to ensure a pressure difference between the flow and return and thus a corresponding flow through the radiators. To regulate the mass flow through a heating circuit depending on the heat demand of the heating circuit, the following is used according to the EP 0 681 148 A2 Among other things, it was proposed to install a pressurized switching valve in the bypass between the heating supply and return lines. This valve would open when a minimum differential pressure is exceeded, thus exposing a temperature sensor in the return section of the bypass to hot heat transfer fluid from the supply line. The resulting temperature difference between the temperature measured by the sensor in the bypass and the return temperature measured by a sensor upstream of the bypass is used to throttle the mass flow of the supply line by means of a control valve. Thus, the mass flow through the heating circuit is controlled, but not the temperature of the heating circuit itself. The invention is therefore based on the objective of designing a heating system of the type in question in such a way that advantageous control of the heating circuit temperature is made possible with comparatively simple design means. Starting from a heating system of the type described above, the invention solves the problem by providing the heating circuit with a switching valve that opens when a minimum pressure difference is applied, and which can be subjected to a pressure difference by means of the circulation pump, which is above or below the minimum pressure difference depending on the heating circuit temperature. As a result of these measures, controlling the circulation pump is sufficient to maintain the heating circuit temperature within a desired range, because the switching valve located in the heating circuit switches depending on the pressure differential created by the circulation pump and the heating circuit temperature. When the minimum pressure differential is exceeded, the switching valve opens, thus connecting the heat consumer to the heating circuit. If the pressure differential falls below the specified minimum value, the switching valve closes, causing the heat transfer fluid to flow through the bypass. By opening and closing the switching valve accordingly, the heating circuit temperature can therefore be influenced without the need for a three-way valve to control the bypass. Only the The speed or power of the circulation pump is controlled via the control unit depending on the temperature of the heating circuit. If a boiler is used as the heat source, the return temperature is typically adjusted to the boiler's requirements using a bypass. In this case, the switching valve is located upstream of the bypass in the return line, with the control unit activating the circulation pump located downstream of the bypass in the return line depending on the return temperature. If the switching valve is subjected to a pressure differential above the minimum pressure differential due to the control by the circulation pump, the consumer, for example, a heat storage tank, is connected to the boiler via the return line. Due to the flow conditions, essentially no heat transfer fluid flows from the supply to the return line via the bypass. If the return temperature needs to be increased, for example, when the boiler is started u