EP2976575A2

EP2976575A2 - Indoor temperature control

Info

Publication number: EP2976575A2
Application number: EP14717162.3A
Authority: EP
Inventors: Geoffrey Thomas Henderson
Original assignee: Invensys Controls UK Ltd
Current assignee: Schneider Electric Controls UK Ltd
Priority date: 2013-03-19
Filing date: 2014-03-19
Publication date: 2016-01-27
Also published as: WO2014147365A3; GB201404881D0; GB2515150B; WO2014147365A2; GB201305015D0; GB2515150A

Abstract

A method and apparatus for control of the heating and air conditioning systems of an environmental space employs means to detect when an air conditioning system is in a cooling mode and to send an inhibit command to the heating system when the air conditioning system is in a cooling mode thereby to inhibit the heating system from providing heat into the environmental space.

Description

INDOOR TEMPERATURE CONTROL

This invention relates to a method of and apparatus for control of temperature of an indoor environmental space such as that of a dwelling, warehouse, retail store, restaurant or the like.

The invention further relates in particular to control of the temperature of an indoor environmental space which is provided with air conditioning and heating systems. More particularly, but not exclusively, the invention relates to a method of and apparatus for controlling the operation of substantially separate heating and air conditioning systems.

The invention relates in particular, though not exclusively, to a method and apparatus which can be employed as a retro-fit to existing equipment that is provided for the heating and air conditioning of an indoor environmental space.

A problem encountered with the management of a temperature of an environmental space is that an air conditioning system can be operating to reduce air temperature to below that at which an independently mounted thermostat initiates operation of the heating system. In consequence the air conditioning system will operate to remove heat that is being introduced into the environment by operation of the heating system. This results in a wasteful expenditure of energy, with significant adverse cost implications.

Conversely, with initially only a heating system in operation, a situation can arise in which a heating system introduces heat into an environmental space which, either solely by operation of the heating system or in consequence of other heat sources such as that from occupiers of the space or sunlight, results in the air conditioning system coming into operation to seek to reduce the air temperature. Again the two systems for heating and cooling are in conflict and a significant waste of energy arises. Although theoretically it would appear possible to minimise the occurrence of concurrent operation of heating and air conditioning systems by ensuring that the control thermostats for each system are set to the same temperature, in reality that is seldom successful. Problems arise due to, for example, differences in the response times of the thermostats for control of the heating and air conditioning systems, temperature differences between the respective locations of the two thermostats, and also, more commonly, the manual override facility conventionally provided whereby occupants are able to select the degree of cooling or heating.

The present invention seeks to provide a method and apparatus which enables the aforedescribed disadvantages of heating and air conditioning systems to be mitigated or overcome. The invention seeks in particular, but not exclusively, to mitigate or overcome said problems in a relatively simple manner which avoids any need to provide an electrical inter-connection with the air conditioning system control mechanism, that commonly being of a bespoke and complex type. Thus it seeks to provide a method and apparatus which can be employed as a retrofit to an existing installation.

In accordance with one aspect of the present invention there is provided a method of control of heating and air conditioning systems of an environmental space wherein means is provided to detect when an air conditioning system is in a cooling mode and wherein an inhibit command is sent to a heating system when the air conditioning system is in a cooling mode to inhibit the heating system from providing heat into the environmental space.

The invention provides also apparatus to be used in an environmental space provided with heating and air conditioning systems, said apparatus comprising a sensing unit for sensing when an air conditioning system is in a cooling mode and for providing an output signal which facilitates inhibition of operation of a heating system when the sensing unit detects that the air conditioning system is in the cooling mode. The invention further provides apparatus for use in said method and comprising the combination of said sensing unit and a heating system thermostat wherein the heating system thermostat provides a demand or inhibit signal to cause the heating system to provide heat into the

environmental space only in the combination of circumstances in which the air conditioning system is not in cooling mode and the heating system thermostat detects a change in the temperature of the environmental space which is below the desired ambient temperature to which the heating system

thermostat is set.

Detection of whether an air conditioning unit is in cooling mode may be achieved by one or more of the following:-

Providing a sensor to detect (e.g. to monitor) air flow leaving the air conditioning unit and to switch off the heating system when an air flow is detected. Thus the heating system would be switched off if the air conditioning unit were in either a fan only (e.g. constant fan operation or a heating mode (for which the fan typically would also be in operation).

Providing a sensor to detect the temperature of air leaving the air conditioning unit and to switch off the heating system when the detected air temperature is significantly colder than a pre-selected temperature.

Detecting the current consumption of at least a component, such as a circulation pump, of the heating system and turning off the heating system when the detected current is indicative of the heating system being in operation to provide heat.

Detecting vibration of the circulation pump of a wet type heating system and turning off the heating system when a vibration sensor indicates that the pump is in operation to circulate fluid. Detecting the total current consumption of the heating system and turning off the heating system when the detected current is indicative of the heating system being in operation to provide heat.

Detecting the current consumption of both the heating system and air conditioning system and turning off the heating system when the detected current is greater than the maximum current that could be taken by the air conditioning system.

Detecting the current and hence power usage of the air conditioning compressor, and turning off the heating system when the compressor is in operation.

Detecting the temperature of an exterior pipe exiting from the air conditioning compressor, or fluid within said pipe, and turning off the heating system when the detected temperature of the exit pipe is higher than a pre-selected temperature, for example at least 150° C.

Detecting the temperature at the exterior of a pipe exiting from an expansion valve at the cool side of the air conditioning system, or fluid within said pipe, and turning off the heating system when the

temperature at the cool side of the air conditioning system expansion valve is low (for example 5°C or lower) unless the ambient temperature of the environmental space is less than a pre-established temperature (for example 15°C). This reference to ambient temperature is to avoid occurrence of a situation in which the air conditioning unit is not in operation but is very cold (e.g. when in an unheated property in winter). Thus this avoids the risk of the heating system being inappropriately inhibited and "frost" damage resulting.

The method and apparatus may comprise only one or alternatively two or more means each for turning off the heating system In the aforedescribed options relating to detecting the temperature of the exterior of a pipe which is part of the air conditioning system the detection of temperature may be achieved by securing a temperature sensor directly to the pipe and providing a wired or wireless communication between that temperature sensor and the heating system, for example to the thermostat of the heating system. The temperature sensor may be of a type suitable for strapping to the exterior of the pipe, thus facilitating a retrofit installation.

The present invention further teaches that the heating system may comprise an information display module, which may be integral with the heating system thermostat, to display an alert that the air conditioning system is detected to be in operation, for example in a cooling mode. Thus if occupiers of the environmental space find that the ambient temperature is too cold and are motivated to adjust the heating system thermostat, the display module of the heating system thermostat would alert them to the fact that the air

conditioning unit is in a cooling mode and inform them or alert them to the need to switch off the air conditioning unit from cooling mode. Optionally there may be an override facility to allow the inhibition of the heating system to be overridden temporarily and/or permanently (e.g. over a protracted time period).

In the case of a wired communication between a temperature sensor secured to an air conditioning system pipe and the heating system, for example the heating system thermostat, preferably the thermostat and/or the temperature sensor is battery powered or powered from a low voltage supply thereby to avoid the need to provide a double insulated construction. In the case of a wireless interconnection between the thermostat and the temperature preferably at least one and preferably each of the thermostat and temperature sensor is battery powered.

In many indoor environmental spaces there will be more than two air conditioning units and in that case operation of the heating system may be inhibited or reduced if either one of the air conditioning units is in cooling mode. Each air conditioning unit may have a detector associated therewith for detecting when it is in cooling mode and each detector may provide a signal to the heating system, for example to the heating system thermostat. In the case of an environmental space provided with more than one air conditioning unit, two or more thermistors associated with the thermostat may be wire in parallel or otherwise.

The heating system may be of a et type comprising fluid which is heated by gas, oil or electricity and then circulated through radiators or other forms of heat exchanges such as forced air flow heaters. Alternatively or additionally the heating system may comprise electric heaters.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings of an indoor environmental space provided with a heating system and an air conditioning system (Figure 1 ) and of part of an air conditioning unit (Figure 2)·

An environmental space 10 comprises a ceiling mounted air conditioning unit 11 and a wall mounted heater 12 in the form of a radiator through which heated water is circulated (see Figure 1 ).

The air conditioning unit 11 comprises an expansion valve 21 , a compressor 22, hot coils 23 and cold coils 24 over which a flow of air is cooled for supply to the environmental space (see Figure 2).

Operation of the air conditioning unit 11 is under the control, by wired connection 13, of a controller module 14 which enables occupiers of the space 10 to select a desired ambient temperature and other features such as airflow speed and direction of airflow.

Operation of the heater 12 is under the control, by wired connection 15, of a thermostat 16 which is sensitive to the ambient temperature of the space 0. Additionally a wireless interconnection is provided between the heater thermostat 16 and a temperature sensor 18 strapped to the exterior of a pipe 20 which exits from the cool side of an expansion valve 21 within the casing of the air conditioning unit.

The heater 16 incorporates a control module which inhibits operation of the heater 12 when the temperature of the expansion valve pipe is below 5°C unless that thermostat has detected an ambient temperature of less than 15°C.

The thermostat additionally incorporates a display which, in the event of the heater operation being inhibited, will flash an alert, such as to display "Aircon", to alert occupants to the need first to switch the air conditioning unit from the cooling mode if they desire a warmer ambient temperature.

Accordingly by, for example, the simple provision of a wireless temperature sensor strapped to a pipe within the air conditioning unit the possibility of the heater and air conditioning systems being in operation simultaneously is avoided or at least substantially minimised.

IC13503GBDE3

Claims

Claims.

1. A method of control of the heating and air conditioning systems of an environmental space wherein means is provided to detect when an air conditioning system is in a cooling mode and wherein an inhibit command is sent to a heating system when the air conditioning system is in a cooling mode thereby to inhibit the heating system from providing heat into the environmental space.

2. A method according to claim 1 and comprising providing a sensor to detect air flow leaving the air conditioning system and to switch off the heating system when an air flow is detected.

3. A method according to claim 1 and comprising providing a sensor to detect the temperature of air leaving the air conditioning system and to switch off the heating system when the detected air temperature is significantly colder than a pre-selected temperature.

4. A method according to any one of the preceding claims and comprising detecting the current consumption of at least a component of the heating system and turning off the heating system when the detected current consumption is indicative of the heating system being in operation to provide heat.

5. A method according to claim 4 and comprising detecting the current consumption of both the heating system and air conditioning system and turning off the heating system when the detected current consumption is greater than the maximum current that could be taken by the air conditioning system.

6. A method according to claim 4 and comprising detecting the total current consumption of the heating system and turning off the heating system when the detected current consumption is indicative of the heating system being in operation to provide heat.

7. A method according to claim 4 wherein the heating system is a wet system comprising a fluid pump and the current consumption of the pump is monitored to provide an indication of whether the heating system is in operation to provide heat.

8. A method according to claim 4 wherein the heating system is a wet system comprising a fluid pump having secured thereto a vibration sensor to provide an indication of whether the pump is in operation to circulate fluid.

9. A method according to any one of the preceding claims wherein the air conditioning system comprises an air conditioning compressor, the method comprising detecting the power usage of the air conditioning compressor and turning off the heating system when the compressor is detected to be in operation.

10. A method according to any one of the preceding claims wherein a pipe exits from the air conditioning compressor and the heating system is turned off when the detected temperature of fluid flowing through the exit pipe is higher than a pre-selected temperature.

11. A method according to claim 10 wherein said pre-selected temperature is at least 150°C.

12. A method according to any one of the preceding claims and comprising detecting the temperature of fluid flowing through a pipe exiting from an expansion valve at the cool side of the air conditioning system and turning off the heating system when the temperature at the cool side of the air

conditioning system expansion valve is low unless the ambient temperature of the environmental space is less than a pre-established temperature.

13. A method according to claim 12 wherein the temperature of fluid flowing through said pipe exiting from an expansion valve at the cool side of the air conditioning system is detected by detecting the temperature at the exterior of said pipe.

14. A method according to any one the preceding claims and substantially as hereinbefore described.

15. Apparatus to be used in an environmental space provided with heating and air conditioning systems, said apparatus comprising a sensing unit arranged to sense when an air conditioning system is in a cooling mode and provide an output signal which facilitates inhibition of operation of the heating system when the sensing unit detects that the air conditioning system is in the cooling mode.

16. Apparatus according to claim 15 and comprising the combination of said sensing unit and a heating system thermostat wherein the heating system thermostat provides a demand or inhibit signal to cause the heating system to provide heat into the environmental space only in the combination of circumstances in which the air conditioning system is not in a cooling mode and the heating system thermostat detects that the temperature of the environmental space is below the desired ambient temperature to which the heating system thermostat is set.

17. Apparatus according to claim 15 or claim 16 and comprising a sensor operable to detect air flow leaving the air conditioning system and to switch off the heating system when an air flow is detected.

18. Apparatus according to claim 15 or claim 16 wherein the apparatus comprises a sensor operable to detect the temperature of air leaving the air conditioning system and to switch off the heating system when the detected air temperature is significantly colder than a pre-selected temperature.

9. Apparatus according to any one of claims 15 to 18 and comprising means for detecting the current consumption of at least a component of the heating system and turning off the heating system when the detected current consumption is indicative of the heating system being in operation to provide heat.

20. Apparatus according to claim 19 and comprising means detecting the current consumption of both the heating system and air conditioning system and turning off the heating system when the detected current consumption is greater than the maximum current that could be taken by the air conditioning system.

21. Apparatus according to claim 19 and comprising means for detecting the total current consumption of the heating system and turning off the heating system when the detected current consumption is indicative of the heating system being in operation to provide heat.

22. Apparatus according to any one of claims 15 to 9 wherein the heating system is a wet system comprising a fluid pump and means is provided to monitor the current consumption of the pump to provide an indication of whether the heating system is in operation to provide heat.

23. Apparatus according to any one of claims 15 to 19 wherein the heating system is a wet system comprising a fluid pump having secured thereto a vibration sensor to provide an indication of whether the pump is in operation to circulate fluid.

24. Apparatus according to any one of claims 15 to 19 wherein the air conditioning system comprises an air conditioning compressor and means is provided for detecting the power usage of the air conditioning compressor and for turning off the heating system when the compressor is in operation.

25. Apparatus according any one of claims 15 to 19 wherein the air conditioning system comprises an air conditioning compressor and wherein means is provided for detecting the temperature of the exterior of a pipe exiting from the air conditioning compressor and for turning off the heating system when the detected temperature of the exit pipe is higher than a preselected temperature.

26. Apparatus according to claim 25 wherein said means is operable to turn off the heating system when the detected temperature is at least 150°C.

27. Apparatus according to any one of claims 15 to 26 wherein the air conditioning system comprises an expansion valve and means is provided for detecting the temperature at the exterior of a pipe exiting from the expansion valve at the cool side of the air conditioning system and for turning off the heating system when the temperature at the cool side of the air conditioning system expansion valve is low unless the ambient temperature of the environmental space if less than a pre-established temperature.

28. Apparatus according to any one of claims 15 to 27 wherein the environmental space is provided with an air conditioning system comprising more than two air conditioning units and means is provided for inhibiting operation of the heating system or reducing operation of the heating system if an air conditioning unit is in a cooling mode.

29. Apparatus according to any one of claims 15 to 28 wherein the sensing unit is provided in combination with an information display module which displays an alert when the air conditioning system is detected to be in operation.

30. Apparatus according to any one of claims 15 to 29 and comprising an override facility to allow the inhibition of the heating system to be overridden temporally and/or permanently.

31. Apparatus according to any one of claims 15 to 30 wherein the heating system comprises at least one radiator which emits heat by radiation and convection.

32. Apparatus according to claim 15 and substantially as hereinbefore described.