GB2389891A

GB2389891A - Boiler control unit

Info

Publication number: GB2389891A
Application number: GB0214476A
Authority: GB
Inventors: Karl-Erik Lindberg
Original assignee: ENERGY CONTROL SYSTEMS INTERNA
Current assignee: ENERGY CONTROL SYSTEMS INTERNA
Priority date: 2002-06-22
Filing date: 2002-06-22
Publication date: 2003-12-24
Also published as: GB0214476D0; AU2003237721A1; WO2004001297A1

Abstract

A boiler control unit (20) for controlling a burner (2) in a heating boiler (1). The control unit (20) includes a delayed cycle controller (21) and a monitoring controller (27), which is arranged to set the delayed cycle controller (21) in a first, conventional on-off-mode of operation and a second delayed cycle mode of operation, at predetermined points of time. The control unit (20) is further arranged to acquire data indicating the energy consumption and the outdoor temperature associated with time intervals corresponding to each of the two operation modes, and to transfer the acquired data to an external computer (13) at a subsequent point of time.

Description

BOILER CONTROL UNIT

Technical field

The invention relates in general to monitoring and control of teiliperaturc controlled heating processes. in particular heating boilers. More spccit;cally, the invention 5 relates to a boiler control unit whicl1 includes a del;'ved cycle controller and a monitoring function for providing int'ormation about the energy ef't'iciency obtained by the delayed cycle controller.

Background of the invention

Ileating, hollers for heating the rooms ot'a building and/or t'or providing tap hot 10 water arc usually dimensioned in such a way that they are thee to nanagc conditions, in which an extremely high heating demand exists, i.e. Durham the coldest winter days. This means that the capacity of'the heating boilers is utilised to the greatest extent during the cold periods of the year. L)uring, the remaining parts of the year, the hollers are over-dimensioned, and consequently. the overall ct't'icicncv 15 is not optimal. A solution to this problem is presented in EP-65 I X7 À. which discloses a delayed cycle controller for a heating boiler equipped with an vn-ot't' controllable burner. The use of such a controller results in an improved overall energy et'ficiency, particularly he periods with low loads. i.e. during moderate and warm seasons.

20 Although such a delayed cycle controller provides an improved energy et't'iciencv.

there is still a need for providing information, e.L:. to the power consumer. about the energy savings actually obtained by the controller. It is thus not possible to assess the real savings provided by the controller and to compare them with the investment necessary tat equip the boiler with StIC31 a controller.

' 05 1 or a modern company. it is essential that energy savings obtained as a result of the investment may be reliably documented. This has an impact on the company's capabilities of delivering a valid environmental account. as well as on the company's environmental profile towards its clients. its suppliers and relevant public authorities.

3() Related background art

EP-65 1 873 discloses a controller for a heating boiler ctiaipped with an on-olf controllable burner. 'I'he boiler is provided with a thermal relay, which provides a temperature responsive signal which is switched on when the temperature in the boiler underpasses a lower temperature level and switched off when the temperature 35 in the boiler exceeds a higher temperature level. When the high temperature limit is reached. the burner is switched off. as also would be the case lathe thermal relay controlled the burner directly. However. when the low temperature limit is reached, the burner is not switched on immediately, as would be the case if the thermal relay controlled the burner directly. Instead, the controller is arranged to measure the

cooling time of the boiler' by measuring the time that has elapsed between the on to-ot'f transition and the off-to-on transition of the signal provided by the thermal relay. 'I'he controller is further arranged to add a certain percentage to this cooling time, resulting in a time delay, and to switch on the burner when this time delay has elapsed. Allis prior art controller provides an improved energy efficiency, but it does not

provide information about the energy savings actually obtained by the controller, compared with the mere use ol'a conventional on-ot'f control without a delay. such I () as the thermal relay.

A further development of' the controller disclosed in EP-65 I X73 is available on the market under the brand'iMicroTllernl''(ct. www.energycontrol-systemsno). 'I'he -'Micro'l'herm" controller also includes an interface for connection of an external computer such as a notebook or hand-lucid computer. Certain parameters, such as I 5 the delay percentage (denoted 'F.-factor") may be set by means of a program executed by the external computer. Also, certain values may be output from the controller to the computer, such as the accumulated on-time of the burner. I lowever.

the controller is not able to accomplish comparative test procedures autonomously.

i.e. oft-line.

2() Summary of the invention

An object of the present invention is to provide a boiler control unit which may provide information about the energy et't'iciency obtained by the delayed cycle , controller, compared to the use of a conventional onof'f'cc>ntroller without a proportional delay, such as a thermal relay.

: A further object of the invention is to provide such a control unit whicl1 provides information about the energy eft'icienc) corresponding to certain time intervals.

Still another object of the invention is to provide such a control unit adapted to provide information about the outdoor temperature, and in particulars to provide such information related to said certain time intervals.

30 Still another object of the invention is to provide such a control unit which may communicate with and be programmed by an external computer.

The above stated objects and further advantages are achieved with a boiler contrc>l unit as set forth in the accompanying set of'claims.

Brief description of the drawings

35 Fig I is a schematic diagram illustrating a heating boiler controlled by a control unit according to prior art,

Fig 2 is a schematic diagram illustrating a heating boiler controlled by a control unit according to the invention, Fig 3 is a schematic diagram illustrating further details of' the control unit according 5 to the invention.

In the l'igures, identical elements are identified with the same reference numerals.

Detailed description of the invention

laid I is a schematic diagram illustrating a heating boiler 1 controlled by a control unit 10 according to the prior art. and more particularly the ''MicroTllerm''

10 controller mentioned above.

I'he boiler 1 comprises a burner 2 controlled in an on-ot'f manner by a delayed cycle controller 11 in the control unit 1(). A thermal relay 6 provides a temperature responsive signal 7 which is switched on when the temperature in the boiler underpasses a lower temperature level. Tlie signal 7 is further switched ol'f when the 15 temperature in the boiler exceeds a higher temperature level.

The delayed cycle controller I I is further arranged to produce a control signal tar input to the burner 9, in order to switch the burner 2 on and of'l'as a function ot'tilc thermal relay signal and the time. More specifically, the control signal is switched off immediately when the thermal relay signal 7 is switched off. and the control 2() signal is switched on at a delayed point ol'time after the thermal relay signal 7 is switched on. The delay is calculated by the: controller 11 as a certain percentage ot' the holler's cooling time. i.e. the time elapsed from the on-ol'f transition to the ol't: on transition of the signal provided by the thermal relay 6. 'I'he control unit 1) is further adapted to communicate with an external computer 13.

25 This prior art solution does not provide means for monitoring and revealing this

i, improved efficiency obtained by the delaved-cveie mode operation of'the contrail unit. I:ig. 2 is a schematic diagram illustrating a heating boiler controlled by a control unit 20 according to the invention. and fig. 3 is a schematic diagram illustrating 30 further details of the control unit 20 shown in fig. 2.

A boiler I comprises an oil burner 2 and a water tank 3 containing water heated by the burner 2. The heating plant f'urthcr comprises a hot-water conduit 5 which may be further connected to a number of taps (not shown) and/or a room heating system (not shown) provided with a shunt valve. circulation pump and radiators. The 35 heating plant further comprises an incoming conduit 4 for supply of cold water as well as a chimney (not shown) for discharging fluid gases resulting from the combustion of oil.

With reference to fig,. 2, the control unit 20 comprises a delayed cycle controller 21.

a time delay register 22, a monitoring controller 27 and a real time clock 28.

Tlle delayed cycle controller 21 is arranged to input a temperature responsive signal 5 7 provided by a thermal relay 6 which is arranged to sense the temperature ol'thc water present in the water tank 3. 'I'he thermal relay 6 causes the temperature responsive signal 7 to be switched on when the temperature in the boiler underpasses a lower temperature level and to be switched off when the temperature in the boiler exceeds a higher temperature level.

10 The delayed cycle controller 21 is further arrancd to pert'orm a delayed cycle control function which is described in the following.

When the thermal relay signal 7 is switched off the controller 91 deactivates the burner control signal 8. which leads to that the burner 2 is turnecI -,t't' 'I'his occurs substantially immediately such as within a couple of' seconds. i.e. with no essential 15 or intentional delay.

The delayed cycle controller 21 is further arranged to calculate the cooling time. i e.

the time of the temperature decay from the high temperature level to a low temperature level. 'I'his is performed by measuring the time elapsing between the on-to-off transition and the oft:to-on transition ot' the signal provided by the thermal 2() relay. The delayed cycle controller 21 is t'urther arranged to read a percentage value t'rom the time delay percentage register 92, and to calculate a time delay, wilicil equals the cooling, time multiplied lay this percentage value.

When the water temperature indicated by the temperature signal 7 fans below the 25 low temperature level. the signal provided by the thermal relay is switched on. I'his off-to-on transition of the thermal relay signal does not lead to that the burner is , switched on immediately. Instead' the controller is arranged k, switch on the burner when the calculated time delay has elapsed. In this way? an extension of the of'l:time of the heating boiler is obtained, which leads to a reduction in the total consumption 2(3 of energy i.e., oil, by the burner 2.

If the percentage value is set to zero, the delayed cycle controller will act as a conventional on-oft'controller, i.e. with the same I'unction as if the thermal relay controlled the burner directly.

The delayed cycle controller 21 is arranged to operate in a t'irst, delayed-cycle mode 35 of operation, wherein the control signal 8 is switched on at a delayed point of' time after the temperature has decreased to the low temperature level. The delayed cycle controller 21 is also arranged to operate in a second? conventional mode of

operation, wherein the control signal 8 is switched on essentially immediately when the temperature has decreased to tite low temperature level. i.c. upon the detection of'an oft:to-on transition in the thermal relay signal 7.

5 The monitoring controller 27, not present in the prior art solution, is arranged to set

the delayed cycle controller 21 in the first and second modes ol' operation at predetermined points of time. This provides for the possibility ol'uccluirin information about the energy efficiency connected with operating the control unit in the delayed cycle operation mode.

1() 'I'he boiler control unit 20 preferably further comprises a real time clocl; 2X.

providing current time and date inl'ormation to the monitoring controller 27.

Advantageously. the control unit 2() is further arranged to calculate the accumulated activated time of' the heater control signal X through an interval. 'I'hc accumulated activated time represents, i.e. is proportional with, the total energy consumption ol' 15 the burner through this interval.

Tlie temperature control unit 20 is further arranged to communicate with an external computer 13 via a communication connection 14 and an interface 2(. 'I'he communication connection 14 may he based on a wired connection. such as a serial communication. or a locals wireless connection SUCH as an infrared or radio based 2() (e.g., Bluetooth) connection. Alternatively, the communication connection 14 nay include a telecommunication network such as the public switched network or a cellular network.

I'he predetermined points of time l'or setting the delayed cycle controller 2 I in (he first and second modes of operation are advantageously included in a data tile that 25 may be input I'rom the external computer 13 during an on-line session. When tle .. session is completed, the boiler control unit 2() operates autonomously. altering ' between the two modes of operation based on the time data contained in the data file. Advantageousiv. the monitoring controller 27 is arranged to generate an output data 3() file indicating the accumulated activated time of the heater control signal 8 through intervals corresponding to the intervals in which the delayed cycle controller is set in the first and second modes of operation, respectively.

The monitoring controller 27 is preferably arranged to generate and store in a memory an output data file, which indicates the accumulated on-time of the heater 35 control signal 8 through intervals which correspond to the intervals in which the delayed cycle controller is set in the first and second modes of operation.

respectively. This data file is downloadable to the computer 13 on request.

An outdoor temperature sensor 24 is preLerablv provided to input a further measurement signal 25 to the monitoring controller 27. Tllis outdoor temperature is not intended to be utilized in the hailer control process. hut it is advantageously 5 stored in a memory included in the output data file, in order to provide to the external computer 13 information about the outdoor temperature in periods corresponding to the intervals in which the delayed cycle controller is set in the first and second modes of operation respectively.

1 he monitoring controller 27 is preferably arranged to acquire outdoor temperatures 1() at a sampling rate that may be set from the external computer, e.g., every 1() seconds. The monitoring controller 97 is further arranged to calculate an average outdoor temperature for each period corresponding to the intervals in which the delayed cycle controller is set in the first and second modes ol operation, respectively. T he calculated average value of accumulated onetime of the burner 15 through the interval is also stored in the output file.

The percentage value may he set and/or read out by the external computer 13 via the interface 26.

In a preferred implementation, the delayed cycle controller 21 and the monitoring controller 27 are functional modules implemented as software modules, Or 2() concurrently execution by a microcontroller employed in the control unit 20. he time delay register 22 and the memory for storing the input data tile and the output data file are parts of a memory connected to the nicrocontrollcr. I he memory comprises a random access memory for variable data and a non-volatile memor! containing fixed data and program instructions. I he implementation ot the prow ant 95 instructions is an ordinary tasl; Ior a person skilled in the art, based on the description given in this specification.

Although the heating device mention in the detailed description is an oil burner. the

skilled person will also realize that the inventions is applicable with other heating devices as well, em. an electrical heater or a gas heater.

A) I:urther variations and alternative embodiments will be evident for the person skilled in the art.

Claims

( I'/'TENT (:LAIMS

I [soiler control unit (2()) tor controlling a heating de\ ice (2) in a holler ( I)-

comprising a delayed cycle controller (21) Ior activating and deactivating said heating device (2), wherein - said delayed cycle controller is operated by a thermal relay (6), providing a temperature responsive signal (7) which is switched on when the temperature in the holler underpasses a lower temperature level and switched off when the tempctaturc in the boiler exceeds a higher temperature Icvel, and wherein I l) - said delayed cycic controller (21) is arranged - to determine the cooling time ot the boiler lay measuring the time elapsing between the on- to-off transition and the otl:to-or1 transition of the signal provi ietl by the thermal relay, - to deactivate tht- heating device (2) essentially at the point of time when the 1 thermal relay signal is switchett oft and - in a first mode ot operation. to activate the heating device (2) at a delay after the thermal relay signal is switched on.

characterized in that the delayed cycle controller is further arranged to. in a second mode ot 2() operation, to activate the heating, des ice (2) essentially at the point ot thee wilen the thermal relay signal is switched on. and that the control unit further comprises a monitoring controller (27), arrant to set the delayed cycle controller in said first anti second modes of operation at predetermined points of time 2 Boiler control unit (aft)) in accordance with claim 1 wherein the controller (2 I) is arranged to determiric the delay as a certain percentage of the cooling time of the holler 3 Boiler control unit (?()) in acCcrdarice with claim I or 2 turtiler comprising a real rime clock (28), providing current time and date information to the monitoring 30 controller (27).

4 Boiler control unit (20) in accordance with one ot the preceding claims.

further arranged to calculate the accumulated activated time of the heater control signal (8) through an interval, indicating the total energy consumption of the heating process through said interval 35 5. Boiler control unit (20) in accordance with claim 4, wherein said monitoring, controller is arranged to generate a data file indicating the accumulated activated time ot the heater control signal (8) through intervals

corresponding to the intervals in which the delayed cycle controller is set in the t'irst and second modes of operation, respectively.

is. Boiler control unit (2()) in accordance \vith claim 5.

5 wherein the monitoring controller (27) is further arranged to input a measurement signal (24) from an outdoor temperature sensor.

7. Boiler control unit (20) in accordance with claim 6.

wherein the monitoring controller (97) is l'urtiler arranged to calculate the average outdoor temperature value through an interval.

10 X. Boiler control unit (20) in accordance with claim 6, wherein said data file produced by the monitoring controller (27) t'urther comprises average outdoor temperature values through intervals corresponding to the intervals in which the delayed cycle controller is set in the first and second triodes of' operation respectively.

15 9. Boiler control unit (20) in accordance with one ot'tile preceding claims.

I'urther arranged to communicate with an external computer ( 12) via a communication connection ( 14) and an interlace (2().

10. Boiler control unit (20) in accordance with claim 9, wherein said predetermined points of time for setting the delayed cycle controller in the t'irst and 90 second modes ot'operation are included in a data t'ile input from the external computer ( 13).

11. Boiler control unit (20) in accordance Will1 one of the claims t)-1(). wherein the control unit (20) is further arranged to input and set by the external computer at least one of the following measures: 95 - time and date of said real time clocl; (28), - said percentage, - a point of time indieathg a start ot'a monitoring period, - a duration of each monitoring interval in the monitoring period. and - a number of monitoring intervals included in the monitoring period.

() 19. Boiler control unit (20) in accordance with claim I 1, \vherein the control unit (20) is further arranged to calculate said predetermined points ot'time t'or setting the delayed cycle controller in the first and second modes of operation, respectively, by utilizing the point ot' time indicating the start of a monitoring period. the duration of each monitoring 35 interval in the monitoring period, and the number ot' monitoring intervals included in the monitoring period.