GB2139783A - Temperature control - Google Patents

Abstract

To mitigate problems caused by thermal inertia, a central heating or air conditioning control system is connected to receive a weather forecast, either by telephone or by radio, from a weather centre, the heating being controlled to take into account the expected changes of the weather.

Description

SPECIFICATION Temperature control The present invention relates generally to the control of ambient temperature in working environments.

Central heating systems which are electrically powered usually rely on heat storage radiators. The system is switched on during off peak hours and stores heat which is used after the electricity supply is disconnected.

A problem with such central heating systems is that they have a high thermal inertia and the heat output cannot be varied rapidly. If, for example, the heating is turned on during one night and in the following day the weather is warm there is not way of avoiding the discomfort of excessive heating.

Conversely, when the weather suddenly turns cold and the heating has not been switched on during the previous night, the temperature cannot be raised.

The same problem is also present in other forms of central heating and air conditioning systems since the space being heated itself has a high thermal capacity and results in a time lag between the control of the central heating or air conditioning system and the required change in the ambient temperature. This becomes particularly noticeable in large installations such as schools and factories.

In order to mitigate the foregoing disadvantages the present invention provides a control system for a central heating or air conditioning system which comprises means for receiving and decoding a metorological forecast and means for controlling the central heating or air conditioning system in dependence upon the forecast.

The invention therefore proposes using the predicted temperature forecast by a weather centre to control the heating or air conditioning system rather the current temperature so as to counteract the thermal inertia in the system.

The electrical signal containing the weather information is preferable received by radio. It has recently been proposed that the carrier frequency of an amplitude modulated broadcast be phase modulated in order to transmit information additional to the amplitude modulation without interfering with the latter. This system, often referred to as subliminal phase modulation, has been proposed, amongst other things, for enabling an electricity generating board to control installations by radio signals for example to switch off certain loads remotely when a national grid system is under peak stress.

It is possible to add to the subliminal phase modulated signal data indicative of a weather forecast and there is channel allocation for permitting such additional information to be included. The rate at which the weather information needs to be updated may be very low compared with the available bit rate and consequently it is possible, for example by allocating different time slots for different regions, to provide a localised weather forecast thereby increasing the accuracy of predictions.

As an alternative, a signal may be received over a telephone line. Such a system would involve a local processor addressing a data base in the weather centre using a conventional modem and can readily be implemented using currently available micro computer equipment. Because of the fact of the invention may be readily implemented by appropriate programming of existing micro-computers, it is believed that a detailed explanation of the hardware is not required within the contents of the present specification and that the invention may readily be put into practise by a person skilled in the art.

If the invention is used in the control of central heating storage radiators which are connected to a meter only providing power at certain times, say night time, then the control unit will be dependent upon the average expected outside temperature in the following day.

If a system is permanently connected to a power source and the invention is employed only to counteract the effects of the time lag caused by the large thermal capacity then this time lag will dictate the extent to which one needs to look ahead in the course of controlling the heating or conditioning system.

With the aid of the invention, if the various factors affecting the amount of heat required for a given temperature rise are known and the expected outside temperature can be calculated from the received forecast, then the heat setting may be constantly varied to achieve the desired working temperature at all times.

The accuracy of weather forecasts is currently high especially if the area covered by the forecast is restricted and the period covered by the forecast is not too long. In the present invention, the forecast need only be for approximately twelve hours and the area covered by the forecast may be very specific.

Consequently, by such predictive control of the central heating system or air conditioning system, the disadvantages of the high thermal capacity of either the radiators or the space being heated may be significantly reduced. Aside from avoiding discomfort, the invention can save on fuel bills in that unnecessarily high heat settings can be avoided.

1. A control system for a central heating or air conditioning system which comprises means for receiving and decoding a metorological forecast and means for controlling the central heating or air conditioning system independence upon the forecast.

2. A control system as claimed in claim 1, wherein the electrical signal containing the weather information is received by radio.

3. A control system as claimed in Claim 2, wherein the weather data is transmitted by sublimal phase modulation of an amplitude modulated broadcast signal.

4. A control system as claimed in Claim 3, wherein weather information for different regions is transmitted in different time slots.

5. A control system as claimed in Claim 1, wherein the meteorological signal is received over a telephone line.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Temperature control The present invention relates generally to the control of ambient temperature in working environments. Central heating systems which are electrically powered usually rely on heat storage radiators. The system is switched on during off peak hours and stores heat which is used after the electricity supply is disconnected. A problem with such central heating systems is that they have a high thermal inertia and the heat output cannot be varied rapidly. If, for example, the heating is turned on during one night and in the following day the weather is warm there is not way of avoiding the discomfort of excessive heating. Conversely, when the weather suddenly turns cold and the heating has not been switched on during the previous night, the temperature cannot be raised. The same problem is also present in other forms of central heating and air conditioning systems since the space being heated itself has a high thermal capacity and results in a time lag between the control of the central heating or air conditioning system and the required change in the ambient temperature. This becomes particularly noticeable in large installations such as schools and factories. In order to mitigate the foregoing disadvantages the present invention provides a control system for a central heating or air conditioning system which comprises means for receiving and decoding a metorological forecast and means for controlling the central heating or air conditioning system in dependence upon the forecast. The invention therefore proposes using the predicted temperature forecast by a weather centre to control the heating or air conditioning system rather the current temperature so as to counteract the thermal inertia in the system. The electrical signal containing the weather information is preferable received by radio. It has recently been proposed that the carrier frequency of an amplitude modulated broadcast be phase modulated in order to transmit information additional to the amplitude modulation without interfering with the latter. This system, often referred to as subliminal phase modulation, has been proposed, amongst other things, for enabling an electricity generating board to control installations by radio signals for example to switch off certain loads remotely when a national grid system is under peak stress. It is possible to add to the subliminal phase modulated signal data indicative of a weather forecast and there is channel allocation for permitting such additional information to be included. The rate at which the weather information needs to be updated may be very low compared with the available bit rate and consequently it is possible, for example by allocating different time slots for different regions, to provide a localised weather forecast thereby increasing the accuracy of predictions. As an alternative, a signal may be received over a telephone line. Such a system would involve a local processor addressing a data base in the weather centre using a conventional modem and can readily be implemented using currently available micro computer equipment. Because of the fact of the invention may be readily implemented by appropriate programming of existing micro-computers, it is believed that a detailed explanation of the hardware is not required within the contents of the present specification and that the invention may readily be put into practise by a person skilled in the art. If the invention is used in the control of central heating storage radiators which are connected to a meter only providing power at certain times, say night time, then the control unit will be dependent upon the average expected outside temperature in the following day. If a system is permanently connected to a power source and the invention is employed only to counteract the effects of the time lag caused by the large thermal capacity then this time lag will dictate the extent to which one needs to look ahead in the course of controlling the heating or conditioning system. With the aid of the invention, if the various factors affecting the amount of heat required for a given temperature rise are known and the expected outside temperature can be calculated from the received forecast, then the heat setting may be constantly varied to achieve the desired working temperature at all times. The accuracy of weather forecasts is currently high especially if the area covered by the forecast is restricted and the period covered by the forecast is not too long. In the present invention, the forecast need only be for approximately twelve hours and the area covered by the forecast may be very specific. Consequently, by such predictive control of the central heating system or air conditioning system, the disadvantages of the high thermal capacity of either the radiators or the space being heated may be significantly reduced. Aside from avoiding discomfort, the invention can save on fuel bills in that unnecessarily high heat settings can be avoided. CLAIMS

1. A control system for a central heating or air conditioning system which comprises means for receiving and decoding a metorological forecast and means for controlling the central heating or air conditioning system independence upon the forecast.

2. A control system as claimed in claim 1, wherein the electrical signal containing the weather information is received by radio.

3. A control system as claimed in Claim 2, wherein the weather data is transmitted by sublimal phase modulation of an amplitude modulated broadcast signal.

4. A control system as claimed in Claim 3, wherein weather information for different regions is transmitted in different time slots.

5. A control system as claimed in Claim 1, wherein the meteorological signal is received over a telephone line.

6. A control system as claimed in Claim 5, the control system comprises a processor communication over the telephone line with a computer in the weather centre.