GB2081444A

GB2081444A - Heat supply determination

Info

Publication number: GB2081444A
Application number: GB8123789A
Authority: GB
Original assignee: Agip Petroli SpA
Current assignee: Agip Petroli SpA
Priority date: 1980-08-06
Filing date: 1981-08-04
Publication date: 1982-02-17
Also published as: DK345881A; BE889863A; IT8024026A0; NO812645L; FR2488424A1; SE8104710L; DE3129757A1; NL8103610A

Abstract

For costing the heat supplied by a central heating installation, a system comprises a temperature governing unit (1), which detects the temperature outside the building by means of a sensor (7), a control unit (2) for determining the desired internal temperature of the building, and sensors (5), (6) for measuring the input and output temperatures of the water circulated in the heating bodies. The temperature signals are delivered to an invoicing unit consisting of an integrator (3) and a counter (4) which provide a summation of heat supplied with respect to time. <IMAGE>

Description

SPECIFICATION Heat supply determination This invention relates to the determination of heat supplied by a heating installation. More particularly, this invention relates to the determination of the quantity (and hence the cost) of heat supplied by central heating installations, which method can be applied to any heating installation irrespective of the kind of fuel which is used.

Heating installations must include an instrument for determining the quantity of heat supplied by the installation, in order for the authorities to apply a tariff to the consumer. The instruments used for this purpose at present are counters for the operation of the installation (heat counters), and calorie-counters which operate by simultaneously detecting the temperature drop of the heating fluid as it circulates in the heating installation, and the rate of flow of the heating fluid.

The former instrument has the defect that the cost of the heat supplied is calculated on the basis of a parameter which is not proportional to the fuel consumption inasmuch as it does not take into account climatic trends and room temperature.

Thus, the calculation of the cost by such a procedure does not differ from bulk payment of the fuel, except for the fact that bulk payment is on an hourly basis and the consumer is allowed to change the number of heating hours. Furthermore the consumer is not permitted to vary the desired room temperature in the heated dwelling because this invoicing method cannot take such a circumstance into account.

The second instrument, even if the manner of its operation is more correct from a theoretical standpoint, may introduce errors in practice, due to the poor reliability of its detectors. In addition, the installation of the instrument requires extensive adaptation of the hydraulic main installation.

According to the present invention, there is provided a method of determining the quantity of heat supplied to a room or building by a heating installation, which method comprises recording the summation of the difference between the temperature outside the room or building and a preset temperature of the room or building to which the heating installation has been set to attain, over the period for which the heating installation operates.

The present invention also provides a system for determining the quantity of heat supplied to a room or building by a heating installation, which system comprises a recording device for effecting a summation of the difference between the temperature outside the room or building and a preset temperature of the room or building to which the heating installation has been set to attain, over the period for which the heating installation operates.

We have thus devised an accounting system which is based, conversely, on the measurement of a parameter which is proportional to the fuel consumption and thus to the heat requirements of a building, which does not require expensive adaptation for its installation and, moreover, permits the heating installation to be governed concurrently with the possibility for the consumer to vary at will the operational mode of the heating installation.

It is known that the heat demand of a building is proportional, at every instant of time, to the difference between the temperatures of the individual heated rooms of the building and the temperature of the outside atmosphere. The fuel consumption is consequently proportional to the summation, over the time of operation of the heating installation, of the difference between the internal and external temperatures. Instruments which are adapted to effect this measurement are already known, but their use in the calculation of the cost of supplied heat meets with difficulties. Thus, they require the installation of probes in the rooms to be heated. Alternatively, they are based, for their operation, on a preselected value of the room temperature.In the former case it is difficuit to select a room which is reliably representative of the thermal conditions of the building as a whole, and it is very difficult to prevent malfunction or alteration of the probes. In the latter case, the consumer is not permitted to vary the mode of operation of the installation inasmuch as the manner of calculating the cost cannot take such variations into account.

An embodiment of the invention provided a method of determining the heat supplied by a heating installation, comprising presetting in a temperature-governing unit the value of the temperature which is desired to maintain in the rooms to be heated, the presetting being obtained by a remotecontrol unit which may also provide for setting the duration of the desired heating period, measuring the outside temperature and the temperature of the water fed to and fed back from the heating bodies, entering in a recording or invoicing unit and for the entire duration of the heating the summation of the difference between the preset room temperature and the temperature outside the building, the signals relative to the preset room temperature and the temperature outside the building being delivered simultaneously to the temperature-governing unit and to the recording or invoicing unit.

Furthermore, an embodiment of the present invention provides an accounting system for calculating the cost of supplied heat, which system comprises (a) a temperature-governing unit with appropriate probes for reading the atmospheric temperature outside of the room or building and the temperature of the water delivered to the heating bodies and returning therefrom; (b) an invoicing or recording unit; and (c) a remote control unit for setting, in the temperature-governing unit, the room temperature which is desired and, optionally, a preselected heating programme, the three units being so interconnected that the signal relative to the preset room temperature and the outside temperature are delivered simu Itaneously to the temperature-governing unit and to the invoicing or recording unit.

In this kind of accounting system a signal relative to the internal temperature is set in the temperaturegoverning unit by an appropriate control device.

This signal is the value of the room temperature on the basis of which the summation of the difference between the internal and the external temperature is measured. By so doing, the difficulties inherent in the poor reliability of the probes placed in the rooms are offset, along with those relative to the possibility of alteration, and it becomes possible to apply a tariff which takes into account the heating programme selected by an individual consumer. The latter fact is of particular importance with a view to saving energy, because the consumer may vary his own heating programme consistently with his personal requirements and is encouraged to save by the fact that the cost is proportional to the actual fuel consumption.The governing unit governs the heating installation as a function of the external temperature by comparing the latter with the preset value of the room temperature, according to a regulation plan which take into account the type of installation.

This regulation can be effected, for example, by commanding a mixing valve or by controlling the fuel burner. The governing unit may be equipped, additionally, with a contact for the control of the circulation pump orthe burner, this contact being open when the temperature outside the building reaches a value which is one degree centrigrade less than the room temperature, and which is closed when the temperature outside the building is two or more degrees centigrade less than the preset room temperature. The contact is also open when the recording or invoicing unit is not working so that the installation cannot operate if the recording or invoicing unit is inoperative.

The remote-control unit is the device which permits the consumer to set, by a daily clock, the desired period of heating and the expected or desired room temperature. The recording or invoicing unit preferably comprises two counters, one of which counts the time during which the heating installation is on and the other of which counts the "consumed daily degrees". Stated another way, the latter counter indicates, in the form of daily degrees, the summation of the difference between the preset room temperature and the temperature outside the building. Stated otherwise, the reading of the second counter is expressed in degrees centigrade multiplied by the hours of operation, divided by 24.

More particularly, the accounting system uses a temperature-governing unit in which it is possible to set, by means of a remote control unit, the temperature the consumer desires to maintain in the rooms to be heated and the preselected heating programme. The temperature-governing unit governs the quantity of heat supplied to the rooms to be heated, and thus the fuel consumption, as a function of the temperature of the water fed to and from the heating bodies, on the basis of the preset temperature and of the temperature outside the building.

Simultaneously, the signals relative to the preset temperature and the temperature outside the building are delivered to the recording or invoicing unit, which preferably comprises of an appropriate integrator and a counter. The latter provides a daily record, during the entire working time of the heating installation, of the summation of the difference between the two aforesaid temperatures and preferably expresses it in degrees centigrade per hours divided by 24 so that in the counter a number is entered which is proportional to the summation and thus proportional to the actual fuel consumption.

Summing up, then, the price paid by the consumer will take into account both the climatic trend of the season and the expected or desired room temperature, as well as the actual hours of heating, i.e. all of the parameters which are relevant to the actual consumption of fuel.

In the accompanying drawing, a schematic representation of a system of the invention is shown by way of example, the system being for use with a heating installation comprising a heat-producing unit for heating water and at least one associated heat-supply unit for the transfer of heat from the water into a room or building.

In a temperature-governing unit 1,the preselected value of the room temperature, along with the heating programme, is set by a remote-control unit 2 which is as the consumer's disposal. The unit 1 adjusts the heating installation on the basis of the temperatures of the water fed to and fed from the heat-supply unit(s), these latter temperatures being read by sensors 5 and 6, and on the basis of the preselected temperature and the temperature outside the building as detected by the sensor 7.Thus, the circulating water of the heating installation is continued to be heated when the difference between the temperatures detected by the sensors 5 and 6 is large but is not heated when the difference is small, and the heating installation operates when the difference between the preselected temperature and the temperature detected by the sensor 7 is large but does not operate when the difference is small. The remote-control unit 2 includes a thermostatic device for switching off the heating installation in the event that the actual room temperature reaches the preselected room temperature. Alternatively, a separate thermostatic device can be used for this purpose.

The electrical signals relative to the temperature outside the building and to the preset room temperature are delivered, via lines 8 and 9, to an integrator 3 and then to a counter 4 which gives a reading in degrees centigrade per hour divided by 24. Thus, on the basis of the reading recorded by the counter, it is possible to charge the consumer an amount which is calculated as the product of the counter reading by a unitary price determined on the basis of the heat demand of the building.

Claims

1. A method of determining the quantity of heat supplied to a room or building by a heating installation, which method comprises recording to summation of the difference between the temperature outside the room or building and a preset temperature of the room or building to which the heating installation has been set to attain, over the period for which the heating installation operates.

2. A system for determining the quantity of heat supplied to a room or building by a heating installation, which system comprises a recording device for effecting a summation of the difference between the temperature outside the room or building and a preset temperature of the room or building to which the heating installation has been set to attain, over the period for which the installation operates.

3. A system as claimed in claim 2, comprising a temperature-governing unit for the heating installa tion, a probe for determining the temperature out side the room or building and for delivering a signal relative to this temperature to the temperature governing unit and to the recording device, and a control unit for delivering a signal relative to the preset temperature to the temperature governing unit and to the recording device.

4. A system as claimed in claim 3, further comprising probes for determining the temperature drop of the heating water circulating in the heating installation and for delivering a signal relative to this temperature drop to th e the temperature-governing unit.

5. A system as claimed in claim 3 or 4, wherein the temperature-governing unit is adapted to control the heating installation by control of a mixing valve or burner of the installation.

6. A system as claimed in claim 3,4 or 5, wherein the control unit is adapted to control the period of operation for the heating installation.

7. A system as claimed in any of claims 2 to 6, wherein the recording device comprises two coun ters one of which records the time of operation of the heating installation and the other of which records the summation of the difference between the tem perature outside the room or building and the preset temperature.

8. A system as claimed in claim 2 substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.