Control System For Panel Heating

Abstract

A control system for panel heating, in particular in the form of underfloor heating systems. In said system a respective valve controls the volumetric flow of hot water through the panel heating of a room and a valve, which divides the volumetric flow of hot water that is supplied to the respective room into two parts, is positioned upstream or downstream of the first valve. The first part of the volumetric flow of hot water is supplied to the panel heating directly or via a restrictor unit, while the second part of the volumetric flow of hot water is supplied to the panel heating via a thermostatically regulated control valve.

Description

The invention relates to a control system for panel heating of the type mentioned in the precharacterizing clause of claim 1.

In recent years, panel heating, especially in the form of floor heating but also in the form of heated ceilings and walls, has been becoming ever more important. The advantages of economical and energy-saving operation, better room-air hygienic conditions, comfort and futuristic, environmentally friendly low-temperature systems are also being exploited in multiple occupancy houses.

The lawmakers have defined specific regulations for the control system of a heating installation. The law controls:

• • 1. The heating water temperature and
  • 2. The heating-water volume flow

The heating-water temperature (inlet temperature) is controlled as standard via a central control system for the entire building, by means of the outside temperature and/or another reference variable.

As is likewise stipulated by the lawmakers, the heating-water volume flow is controlled by means of automatically acting devices for controlling the room temperature, on a room-by-room basis.

The control valve which is influenced by the “room air temperature” reference variable varies the heating-water volume flow with the aim of varying the heat emitted from the panel, for example in the floor, to the room.

In the case of panel heating, the type of room-by-room temperature control that is known for space heaters using the room temperature as a reference variable, by virtue of the lack of any alternative, is not directly suitable, since panel heating reacts too slowly for this purpose. The floor fittings which are normally used in modern floor heating systems result in variation of the heat output becoming effective only after about 2 hours. This time between the action of the control valve and the start of effectiveness in the room is referred to as the control time or delay time. This also applies to panel heaters in the form of heated walls and ceilings.

This disadvantageous effect of this delay time is ameliorated by the physical phenomenon known as the “self-regulation effect”. This natural effect regulates the power output from the heating panel in direct proportion to the temperature difference between the heating-panel temperature and the room temperature. This effect, which has a very powerful effect because of the small temperature difference especially with panel heating, is independent of control systems and takes place at the same time as changing room-temperature conditions. This reduces the poor, slow response of the control valve.

The invention is based on the object of providing a control system of the type mentioned initially, which has an improved control response.

This object is achieved by the features specified in claim 1.

Advantageous refinements and developments of the invention are specified in the dependent claims.

The invention is based on the discovery that, if the amount of heat which must be supplied to the room in accordance with the calculated heat load in order to reach the required room temperature is analyzed, a distinction must be drawn between by far the majority of the heat which must be supplied permanently and a small component which is influenced by external influences such as solar radiation, external heat, fans etc.

If these disturbance-variable influences did not exist, then it would be sufficient to match the inlet temperature to the outside temperature for the entire building. There would be no need for additional room-by-room control.

The proportion of the heating-water volume flow which corresponds to the permanently supplied amount of heat should not be influenced by a slow-reaction control valve.

In the control system according to the invention, the heating-water volume flow is split by a valve in a freely variable ratio into two volume flow elements, in which case each volume flow element can be influenced by at least one different type of controlled variable. These two volume flows may be varied between 0 and 100%, with the first part of the heating-water volume flow being supplied directly to the panel heating, while the second part of the heating-water volume flow is supplied to the panel heating via a thermostatically controlled control valve.

In one embodiment, the valve is designed such that it allows the proportional components of the first part of the heating-water volume flow, which is supplied directly to the panel heating, and of the second part of the heating-water volume flow, which is supplied via the thermostatically controlled control valve, to be adjusted.

In this case, the valve can permanently set the proportional component of the first and second part of the heating-water volume flow, or the proportional components of the heating-water volume flow may be adjustable.

In the first case, the valve may have a fixed shutter which governs the second part of the heating-water volume flow which is supplied to the panel heating.

In the second case, the valve may itself have an adjustment capability for the magnitude of the two volume-flow elements, or a further adjusting valve for the first part of the heating-water volume flow which is supplied directly to the panel heating can be arranged between the valve and the inlet of the panel heating.

In one embodiment, the valve may be remotely controllable both for the first part and for the second part of the heating-water volume.

The valve which controls the overall heating-water volume flow may be an adjusting or shut-off valve for hydraulic regulation of all of the panel heating in a heating installation, and precedes or follows the valve which controls the ratio of the two volume flow elements.

According to one preferred refinement of the invention, the valve which controls the ratio of the two volume flow elements and the thermostatically controlled control valve, and if appropriate the adjusting valve and the valve which controls the overall heating-water volume flow, can be arranged in a common valve block, which has one output at which the first and second parts of the heating-water volume flow are combined with one another, and which is connected to the panel heating.

The invention will be explained in more detail in the following text with reference to the drawings, in which:

FIG. 1 shows a first embodiment of the control system with the volume flow elements permanently set,

FIG. 2 shows an embodiment of the control system in which the volume flow elements can be varied,

FIG. 3 shows a further embodiment of the control system in which the volume flow elements can be varied.

FIG. 1 shows a first embodiment of the control system.

In this embodiment of the control system, the outlet of the adjusting or shut-off valve 10 is connected to a valve 6 which splits the overall heating-water volume flow 1 from the inlet into two heating-water volume flow elements 2, 3, of which one volume flow 3 is supplied directly to the panel heating 11, which is connected to the heating-system return 12. The valve 6 is in this case formed by a shutter, which results in a fixed ratio between the two flow elements 2, 3 of the heating-water volume flow 1. The volume flow element 2 is likewise supplied via a thermostatically controlled control valve 4 to the inlet of the panel heating 11 which, for example, is floor heating. In this embodiment, the ratio between the two flow elements 2, 3 of the heating-water volume flow 1 is therefore predetermined, and is fixed, by the design.

In contrast, in the embodiment shown in FIG. 2, the valve is formed by a valve 5 which can either be operated from the outside or is remotely controllable. The function of this valve 5 is the same as in the case of the embodiment shown in FIG. 1, but with the capability to adjust the ratio of the volume flow elements 2, 3 in this case. In this case, the proportion flowing via the thermostatically controlled control valve 4 may be varied either towards 0 or towards 100%.

The proportion of the second volume flow 2 should become greater, the greater the extent that disturbance variables, such as external heat, solar radiation, the direction of the sky, etc can influence the environment in the individual room.

Changes can be made later by a change in the user behavior, resulting in a change in the setting ratio.

The reference variable or controlled variable which controls the drive for the valve 5 or 7 is a different variable than that for the drive for the valve 4. The drive for the thermostatically controlled valve 4 may be a thermostatic remote sensor, an electrical actuating motor or a time switch.

The hydraulic matching, that is to say the setting of the overall heating-water volume flow 1 in order to cover the heating load for the room, is achieved by operating the valve 10. This allows the overall heating-water volume to be shut off at the same time. Although the drawings show this valve 10 in an arrangement upstream of the valves 5, 6, it may also be connected downstream from these valves.

In the embodiment shown in FIG. 3, the same valve 6 is used as that in FIG. 1 with a fixed shutter (although it is also possible to use the valve 5 as shown in FIG. 2), but a variable valve 7 is arranged in the path of the first volume flow element 3, allowing adjustment of this first volume flow element.

The reference or control variables which control the drive for the valve are the surface temperature of the floor or the flooring temperature (state of charge), or the temperature of the heating medium.

According to one preferred refinement of the invention, all of the valve elements 10, 5/6, 4, and if appropriate 7, shown in FIGS. 1 to 3 are combined to form a single valve block, which is connected on one side to the inlet and on the other side to the panel heating, so that there is no need for the extensive distribution systems that are otherwise used for panel heating systems in dwellings, and these can be replaced by a single ring main or spur-line system.

The arrangement in a common valve block means that the valve cones of different valves, such as the valves 4 and 7, can be operated by a common spindle, for example the spindle of an electrical control drive, by combined measurement and control commands, or for frost-protection and emergency-operation settings.

Claims

1. A control system for panel heating, in which a valve is provided in order to control the heating-water volume flow through the panel heating in a room, wherein the valve is preceded or followed by a valve which splits the heating-water volume flow that is supplied to the respective room into two parts, with the first part of the heating-water volume flow being supplied directly or via a restrictor device to the panel heating, while the second part of the heating-water volume flow is supplied to the panel heating via a thermostatically controlled control valve.

2. The control system as claimed in claim 1, wherein the valve is designed to adjust the proportional components of the first part of the heating-water volume flow, which is supplied directly to the panel heating, and of the second part of the heating-water volume flow, which is supplied via the thermostatically controlled control valve.

3. The control system as claimed in claim 2, wherein the valve has a fixed setting for the proportional components of the first and the second part of the heating-water volume flow.

4. The control system as claimed in claim 2, wherein the proportional components of the heating-water volume flow can be adjusted by means of the valve.

5. The control system as claimed in claim 1, wherein the valve has a fixed shutter which governs the second part of the heating-water volume flow which is supplied to the panel heating.

6. The control system as claimed in claim 4, further comprising a further adjusting valve for the first part of the heating-water volume flow is arranged between the valve and the inlet of the panel heating.

7. The control system as claimed in claim 1, wherein the valve is remotely controllable.

8. The control system as claimed in claim 1, wherein the valve is an adjusting or shut-off valve for hydraulic regulation of all of the panel heaters in a heating installation, and precedes or follows the valve.

9. The control system as claimed in claim 1, wherein the valve, the valve and the thermostatically controlled control valve as well as the adjusting valve are arranged in a common valve block, which has one output at which the first and second parts of the heating-water volume flow are combined with one another.