SE1850363A1

SE1850363A1 - An arrangement for limiting peak loads in heating energy consumption

Info

Publication number: SE1850363A1
Application number: SE1850363A
Authority: SE
Inventors: Hannu Koskela; Jukka Koskela
Original assignee: Smart Heating Oy
Priority date: 2017-04-03
Filing date: 2018-03-29
Publication date: 2018-10-04
Also published as: FI20175308A; FI127418B; NO20180440A1; SE543114C2; NO344076B1

Abstract

The invention relates to a method for limiting the heating load of a building, an arrangement for limiting the heating load, a device for limiting the heating load, and a computer program product for use in limiting the heating load of a building. In the invention, a load limiting device is used for receiving (41) meter pulses, reflecting the heating energy consumption, from the energy meter of the building to the load limiting device. The load limiting device is used for computing (42) the average heating load of the building between two successive meter pulses. The load limiting device is used for comparing (43) the computed average heating load with a first limit value set for the heating load. If the first limit value set for the heating load is exceeded, measures are taken (44) to restrict the valve of at least one district heating network, for reducing the heating load of the building. In the limiting measures, the load limiting device is used for correcting the temperature measurement values of the supply water meters of the circulating water system in the building upwards, whereby the actual temperature control device of the building will reduce the intake of thermal energy from the district heating network correspondingly.

Description

An arrangement for limiting peak loads in heating energy consumption The invention relates to a load limiting device to be utilized in limiting peak loads inheating energy consumption, a load limiting arrangement, a load limiting method,and a computer program product to be utilized in the load limiting method.

Prior art Housing associations are normally invoiced for district heating on the basis of twoitems: a basic fee and an energy unit fee. The basic fee is normally based on time,and it is generally expressed in ê/year or ê/month. Payment for energy is madeaccording to the consumption, based on the energy unit fee. The energy unit fee fordistrict heating indicates the price for district heating energy per one energy unit,generally ê/MWh or ê/kWh.

The basic fee is normally not affected by the amount of district heating energy paid,but it is determined at least partly by either the measured peak load or the districtheating water ﬂow rate m3/h (volume water ﬂow rate, contract water ﬂow rate, sub-scription water ﬂow rate) during the peak demand. The basic fee may be based onother factors as well, such as the amount of cooling in district heating. However, thepeak load is normally the greatest single factor determining the basic fee. The pur-chaser and the supplier may agree upon a calculated level for the peak load, or itmay be determined according to the actual peak load measured. This peak loadmay be checked, for example annually, by either the supplier or the purchaser.Some district heating companies have an annual automatic check on the peak loadon the basis of the highest load per hour measured within a year, that is, the highestaverage district heating load per hour.

The share of the basic fee in the district heating bill is normally smaller than theshare of the energy unit fee. However, the basic fee may be high as well, in thelargest apartment buildings for example 10,000 to 20,000 ê per year. Savings in theenergy unit fee can be achieved by reducing the energy consumption of the building,for example by increasing insulation or by using heat pumps, whereby less energyis purchased. These are normally expensive but proﬁtable measures. Savings in thebasic fee are more difﬁcult to achieve, even if the above mentioned measures nor-mally reduce the peak load and thereby the basic fee to some extent as well.

Various arrangements for limiting the heating output of heating systems of buildingsare presented in documents DE 19604189, DE 19859364 and EP 2985535.

Figure 1a exempliﬁes an arrangement 10 of prior art for controlling district heatingin a building, to be utilized in various buildings, such as apartment houses. Temper-ature control in the building is performed by a control device 1 so that the roomtemperature in different parts or apartments of the building is maintained within apredetermined temperature range. The temperature control device 1 may be a pro-grammable electronic control device comprising a processor for executing controlcommands and a suitable amount of memory for storing the control algorithmneeded for controlling the temperature. Furthermore, the temperature control device1 comprises various inputs for receiving the required temperature measurementdata, and various outputs for controlling at least one valve 4 (reference 1a) of adistrict heating network 10A, for controlling the heat consumption of the building.The temperature control device 1 may also comprise outputs for controlling valvesof a heating system 100A. The temperature control device 1 may also comprise auser interface with a keypad and a display. The heating system 100A which will bementioned in the description hereinbelow may be, for example, a radiator network,an underﬂoor heating system, or a liquid circulation system relating to air heatingequipment, or a combination of these.

Outdoor temperature is measured by a temperature sensor 2 connected to one inputof the control device 1.

The temperature of the water circulating in the heating system of the building ismeasured by a supply water sensor 3 connected to the pipe of the heating system100A, at the end next to the heat exchanger. The supply water sensor 3 is connectedto one input of the control device 1, via which the temperature value 3a of the watersupplied to the heating system is input in the control device 1. By using the meas-urement value 2a for the outdoor temperature and the measurement value 3a forthe temperature of the water supplied to the heating system 100A, the temperaturecontrol device 1 is conﬁgured to control the valve 4 of the district heating network10A so that the temperature in the building is maintained within predetermined limitvalues for the temperature. For adjusting the temperature, the temperature controldevice 1 transmits a control command 1a to the valve 4. By the control command1a, the temperature control device 1 may either increase or decrease the ﬂow rateof heating water in the pipe from the district heating network 10A to the building, bychanging the setting of the valve 4. ln many cases, the same control device 1 is also used for adjusting the temperatureof domestic hot water in the building, in the same way as for adjusting the temperature of the water in the heating system 100A. This adjustment is not shownin Fig. 1a.

Figure 1b shows an example in which the peak value 13 for the heating load in thebuilding in a time interval from 12 to 14 exceeds an exemplary limit value 5 for aheating load determining a basic fee, the limit value being 300 kW in the exampleof Fig. 1b. Because the peak load 13 has exceeded the limit value 5 for the basicfee for at least an hour, an increased basic fee to be charged for the building willalso apply to a time 11 when the heating load has been lower than the limit value 5of the heating load set for the basic fee. ln the example of Fig. 1b, it is possible to measure the volume water flow rate in-stead of the heating load of the building in the district heating system. Thus, Fig. 1bmay illustrate the quantity of district heating water that has ﬂowed from the districtheating system through the heat exchanger of the building. ln this case, the limitvalue may be a quantity of district heating water in m3, for example per one hour. ln a heating system of prior art, a problem with the heat control may be the determi-nation of the basic fee for the whole year on the basis of a single peak of relativelyshort duration in the consumption of heating energy. lf the peak in the consumptionof heating load can be prevented, the saving in the basic fee of district energy is, atbest, thousands of euros per year.

Aim of the invention The aim of the invention is to present a new control method reducing the costs ofenergy for heating a building, a control arrangement, a load limiting device, and acomputer program product to be utilized in the control method.

The aims of the invention are achieved by a control method, a control arrangement,a control device, and a computer program product to be utilized in the controlmethod, by which a momentary peak demand of energy for heating a building isdistributed over a period of time longer than the original period of peak load. Theinvention is used to prevent a single heating load peak of short duration, needed forheating a building, from exceeding a limit value set for changing the basic fee. 4 The invention has the advantage that it can be utilized in old as well as new build-ings, and the utilization of the invention does not require changes in the existingheating control system or heating system. lt is another advantage of the invention that the load limiting device according to theinvention can be installed in parallel with an existing temperature control device sothat no changes need to be made in the temperature control algorithm applied in thetemperature control device.

Yet another advantage of the invention is that the heating load needed for heatingdomestic hot water can be reduced in connection with the control of the heatingsystem, to boost the control.

Yet another advantage of the invention is that even if the peak load of district heatingwere limited during a consumption peak, the demand for heating the building canbe met within the temperature range set over a longer period of time, because thepurchased total amount of heating energy is not changed but merely distributed overmore hours after an anticipated load peak.

The method and the apparatus according to the invention are characterized in whatwill be presented in the independent claims.

The method according to the invention for limiting the heating load of a building,wherein an outdoor thermometer is used for measuring the outdoor temperature anda supply water sensor is used for measuring the temperature of water supplied to acirculating water system, is characterized in that a load limiting device is used for- receiving meter pulses from an energy meter of the building to the load limitingdevice, reﬂecting the heating energy consumption, - computing the average heating load of the building between two successive meterpulses in the load limiting device, - comparing the computed average heating load with a proactive upper limit set forthe heating load, and if the proactive upper limit set for the heating load has beenexceeded, - activating the restricting functions of the valve of at least one district heating net-work, for reducing the heating load of the building by heating the supply water sen-sor of at least one circulating water system by means of a heating resistor.

The arrangement according to the invention for limiting the heating load of a build-ing, comprising a temperature control device for the building, an outdoor thermom-eter, a supply water sensor for measuring the temperature of supply water enteringthe circulating water system of the building, is characterized in that the control ar-rangement further comprises a load limiting device which is conﬁgured -to receive meter pulses from the energy meter of the building to the load limitingdevice, reﬂecting the heating energy consumption, -to compute, in the load limiting device, the average heating load consumed in thebuilding between two successive meter pulses, -to compare, in the load limiting device, the computed heating load with the proac-tive upper limit set for the heating load, and if the proactive upper limit set for theheating load has been exceeded, -to take action for limiting at least one valve in the district heating network, for re-ducing the heating load of the building by heating a supply-water sensor of at leastone circulating water system by means of a heating resistor.

The device according to the invention for limiting the heating load of a building ischaracterized in that it comprises means -for receiving meter pulses from the energy meter of the building to the load limitingdevice, reﬂecting the heating energy consumption, -for computing the average heating load consumed in the building between twosuccessive meter pulses, -for comparing the computed average heating load with a proactive upper limit setfor the heating load, and if the proactive upper limit set for the heating load has beenexceeded, -for activating the restricting functions of the valve of at least one district heatingnetwork, for reducing the heating load of the building by heating the supply-watersensor of at least one circulating water system by means of a heating resistor.

The computer program according to the invention is characterized in that it com-prises code means which are conﬁgured -to receive meter pulses from the energy meter of the building to the load limitingdevice, reﬂecting the heating energy consumption, -to compute, in the load limiting device, the average heating output consumed inthe building between two successive meter pulses, -to compare, in the load limiting device, the computed average heating load with aproactive upper limit set for the heating load, and if the proactive upper limit set forthe heating load has been exceeded, 6 -to activate the restricting functions of the valve of at least one district heating net-work, for reducing the heating load of the building by heating a supply-water sensorof at least one circulating water system by means of a heating resistor.

Some advantageous embodiments of the invention are presented in the dependentclaims.

The basic idea of the invention is the following: Using the device according to theinvention for limiting the heating load, it is possible to prevent an increase in thebasic fee of district energy for a building because of a short-term peak in the heatconsumption. The load limiting device according to the invention is used to limit thedistrict heating intake of a building, preferably only from the beginning of a foresee-able short-term peak load. The peak load is foreseen by the load limiting devicewhen a proactive upper limit, predicting a load peak and set in the load limiting de-vice according to the invention, is exceeded.

After the consumption of thermal energy in the building has been decreased by loadlimiting measures according to the invention to a predetermined load level, the loadlimiting device reduces the load limiting measures, preferably gradually. Thus, whenthe load limiting device according to the invention is used, the district heating energyneeded for heating is thus distributed over more hours after the beginning of a fore-seeable load peak. Thus, for each hour when load limiting is applied in the building,the average heating load will remain on a level that does not cause an increase inthe basic fee. Nevertheless, the amount of heating energy may preferably be similarto the amount that would have been consumed without using the load limiting deviceaccording to the invention. ln the control arrangement of the invention, the meter pulses transmitted by the dis-trict heating energy meter of the building are received by the load limiting deviceaccording to the invention. One meter pulse corresponds to an amount of energydetermined for the system. By applying the time between two successive meterpulses, the load limiting device according to the invention computes the averageheating load for the time between the pulses. lf the result of the computation is thatthe heating load has exceeded a proactive upper limit predetermined for the control,or if exceeding is foreseeable on the basis of a trend, the load limiting device ac-cording to the invention triggers measures for limiting the load. The strength andpromptness of the load limiting measures preferably increase upon approaching thelimit value for the basic fee speciﬁc to the building.

The load limiting device according to the invention can be installed in parallel with atemperature control device already existing in the building so that the operation ofthe temperature control device is not changed. ln the control arrangement accordingto the invention, the heating load of the building is preferably adjusted by heatingthe supply water sensor of at least one circulating water system in the building bymeans of a resistor. The adjustable circulating water system may be either a heatingsystem or a hot water supply system. Thus, according to the invention, the temper-ature control device controlling said circulating water systems of the building re-ceives a corrected measurement value higher than the actual value, and, in re-sponse, reduces the ﬂow of hot water supplied from the district heating network tothe heat exchanger of the building. ln a preferred embodiment of the invention, the load limiting device according to theinvention is electrically connected to such an input of the temperature control devicein the building, via which the operation of the temperature control device can becontrolled so that the ﬂow of heating water from the district heating network to theheat exchanger of the building is reduced. ln a preferred embodiment of the invention, the load limiting device according to theinvention can also be equipped with the functions of the actual temperature controldevice, whereby the existing temperature control device can be replaced by the loadlimiting device according to the invention. ln the following, the invention will be described in detail. ln the description, referencewill be made to the appended drawings, in which Fig. 1a exempliﬁes a control arrangement for a prior art heating system with wa-ter circulation; Fig. 1b exempliﬁes the load behaviour of the control arrangement for the heatingsystem with water circulation, in relation to time; Fig. 2a exempliﬁes a control arrangement for a heating system with water circu-lation according to a ﬁrst embodiment of the invention; Fig. 2b exempliﬁes a control arrangement for a heating system with water circu- lation according to a second embodiment of the invention; Fig. 2c exemplifies a control arrangement for a heating system with water circu-lation according to a third embodiment of the invention; Fig. 2d exempliﬁes a temperature sensor to be utilized in embodiments accord-ing to the invention; Fig. 3 exempliﬁes the load behaviour of a heating system with water circulationaccording to the invention, with respect to time; Fig. 4 shows an exemplary ﬂow chart of the functional main steps of a controldevice according to the invention in controiling a heating system with wa-ter circulation; and Fig. 5 exempliﬁes the functional elements of a load limiting device according to the invention.

The embodiments in the following description are presented as examples only, anda person skilled in the art may also carry out the basic idea of the invention in someother way than what is described in the description. Although the description mayrefer to a certain embodiment or embodiments in several contexts, this does notmean that the reference would be directed towards only one described embodimentor that the described feature would be usable in only one described embodiment.The individual Characteristics of two or more embodiments may be combined andnew embodiments of the invention may thus be provided.

Figures 1a and 1b have been described in connection with the description of theprior art.

Figure 2a shows an arrangement 20 according to a ﬁrst embodiment of the inven-tion for controiling the heating load of a building.

The load control arrangement of Fig. 2a comprises a load limiting device 6 accordingto the invention, installed in parallel with a district heating control arrangement 10 ofprior art as shown in Fig. 1a. The load limiting device 6 is connected to the districtheating meter 7 of the building by either a wired or a wireless communication link.Preferably, the load limiting device 6 is used for limiting at least one of the circulatingwater networks belonging to the heating water system 100A. Common circulatingwater systems include a radiator system and an underﬂoor heating system. 9 The load limiting device 6 is also electrically connected to a heating resistor 8 via aconnection 6a. The load limiting device 6 controls the heating resistor 8 of the supplywater sensor 3 of the heating system 10OA according to a limiting level, for exampleso that the heating by the heating resistor 8 follows directly a limiting level of 0 to100% determined by the load limiting device 6. When the limiting is at the maximum,the heating resistor is heated at maximum output. The output of the heating resistor8 is determined according to the sensor used, and it is preferably in the order of 1to 10 W. ln principle, the load limiting device 6 according to the invention does not adjust theheating of the building, but it only inﬂuences the temperature measurement dataobtained by the temperature control device 1 of the building. Therefore, the loadlimiting device 6 according to the invention can be installed in parallel with any tem-perature control device 1 already existing in the building.

On the basis of the load measured by it, the load limiting device 6 determines theload limiting level which may be given, for example, as a percentage between 0 and100%. The limiting is increased when the heating load measured by the load limitingdevice 6 exceeds a predetermined proactive upper limit, and correspondingly, theload limiting is reduced when the measured heating load drops below a predeter-mined proactive lower limit.

The district heating meter 7 transmits a meter pulse 7a reﬂecting the energy con-sumption of the building after a predetermined amount of thermal energy has beenconsumed. Preferably, the district heating meter may transmit a meter pulse 7a, forexample, after the building has consumed, for example, 1 kWh or 10 kWh of thermalenergy. Alternatively, the meter pulse 7a may also be generated on the basis of theamount of district heating water that has passed through the heat exchanger of thebuilding. The amount of thermal energy needed for generating the meter pulse 7ais an amount of energy that can be determined according to the apparatus in ques-tion. Preferably, the amount of energy deﬁned for the meter pulse 7a is such thatthe district heating meter 7 transmits several meter pulses 7a per hour in a coldheating season.

The load limiting device 6 according to the invention receives the meter pulse 7atransmitted by the district heating meter 7. After this, the load limiting device 6 com-putes the average load between the preceding meter pulse and the last received meter pulse, by dividing the amount of energy determined by the meter pulse by thetime between the meter pulses.

At least one proactive upper limit is set in the load Iimiting device 6; if this limit isexceeded, the load limiting device 6 will switch on an electric current through theheating resistor 8 of the supply water sensor 3 of the heating system 100A. The heatgenerated by the heating resistor 8 heats 9 the supply water sensor 3 of the radiatornetwork 100A. ln this way, the temperature measured by the supply water sensor 3 of the heatingsystem 100A can be changed so that the temperature data 3a from the supply watersensor 3 to the temperature control device 1 of the building is higher than the realvalue. As a result, the temperature control device 1 will transmit a control command1a to the valve 4 of the district heating network 10A, containing a new setting for thevalve 4. The change in the setting of the valve will throttle the port of the valve 4.Thus, the change in the setting of the valve 4 will reduce the ﬂow of hot water fromthe district heating network 10A by a rate which depends on the changed tempera-ture value 3a of the supply water meter 3. lf the utilization of a communication bus is an option for data transmission in thedistrict heating meter 7, various measurement data can be transferred from the dis-trict heating meter 7 to the load limiting device 6 according to the invention via theutilized communication bus, in real time if necessary, instead of the meter pulses 7adescribed above. Thus, the load limiting device may utilize the load data given bythe district heating meter, wherein the load data does not have to be determined bythe load limiting device on the basis of the meter pulses. Examples of communica-tion buses of prior art, utilized in heating systems of buildings, include M-Bus andModbus.

As a result of the reduced ﬂow from the district heating network 10A, less thermalenergy from the district heating network is needed in the building during the loadlimiting measures when the load limiting device 6 is used, compared with the controlsystem of prior art (Fig. 1) with no arrangement for limiting the peak load. Thus, byusing the load limiting device 6 according to the invention, it is possible to preventexceeding the load limit used as a basis for the basic fee for district heating, wherebysavings are made in the basic fee costs. 11 Figure 2b shows an arrangement 20A for controlling the heating load in a heatingsystem according to a second embodiment of the invention. ln the arrangement 20A for controlling the heating load in the heating system 100Ashown in Fig. 2b, the load limiting device 6 according to the invention is connectedto at least one input of a temperature control device 1 in the building via a commu-nication link 6c. ln this embodiment, the load limiting device 6 according to the in-vention is conﬁgured to revise the target temperature value of the supply water sen-sor 3 of the heating system 100A preferably downwards by using the communicationlink 6c. Thus, the temperature control device 1 limits the ﬂow of water from the dis-trict heating network 10A by transmitting a new setting in a control command 1a tothe valve 4, to reduce the ﬂow of hot water in the district heating network 10A. ln this embodiment, it is preferably not necessary to utilize a heating resistor 8 forheating the supply water sensor 3 in the heating system 100A.

Figure 2c shows an arrangement 2OB for controlling the heating load according toa third preferred embodiment of the invention. ln this embodiment, an arrangement for controlling a hot water supply system 100Bis also introduced in parallel with the arrangement 20A for controlling the heatingsystem 100A shown in Fig. 2a. Heat is supplied from a district heating network (ref-erence 1OB) via a heat exchanger to the hot water supply system 100B as well.

In the control arrangement 2OB of Fig. 2c, the thermal energy intake of the buildingfrom the district heating networks 10A and 10B is controlled, according to the inven-tion, by means of corrected temperature data from both the supply water sensor 3of the heating system 100A and the supply water sensor 33 of the hot supply watersystem 100B. ln this embodiment, it is also possible to change the temperature measured by thesupply water sensor 33 of the hot supply water system 100B so that the temperaturedata 33a from the supply water sensor 33 of the hot supply water system 100Bentered in the temperature control device 1 of the building is higher than the actualtemperature. As a result, the temperature control device 1 will transmit a controlcommand 1b to the valve 34 of the district heating network 10B, to change the set-ting of the valve 34. After receiving the control command 1b, the valve 34 will reducethe port of the valve 34 of the district heating network 10B to comply with the new 12 setting. The change in the setting will reduce the ﬂow rate of district heat from thedistrict heating network 1OB to the heat exchanger of hot supply water in the build-ing, by a value depending on the va|ue of the changed temperature 33a indicatedby the supply water sensor 33. ln this embodiment, the load limiting device 6 according to the invention may heateither one or both of the heating resistors 8 or 38 of the district heating network 10Aor the district heating network 1OB, on the basis of the need for control computed inthe load limiting device 6. lf the load limiting device 6 heats both of the heating re-sistors 8 and 38, their heating capacities may be preferably unequal, for achievingan optimal load control in such a way that the users of the building will not sufferfrom temperature changes.

The arrangement shown in Fig. 2c for controlling the supply water may also be uti-lized in the control arrangement of Fig. 2b where no separate heating resistors 8and 38 are used. ln this preferred embodiment, the load limiting device 6 accordingto the invention is configured to revise the target temperature values of the supplywater sensor 3 of the heating system 100A and the supply water sensor 33 of thehot supply water system 10OB downwards, when the district heating load is limited.Thus, the temperature control device 1 will reduce the ﬂow of water either in thedistrict heating network 10A supplying the heating system 100A, or in the districtheating network 1OB supplying the supply water system 10OB, or in both, by sendingcommands to the valves 4 and 34 to change the settings, in order to reduce the ﬂowin at least one of the district heating networks.

Figure 2d shows how the heating resistor 8 or 38 in the control arrangement of theinvention can be connected to a supply water sensor 3 or 33 in a water pipe 35 in aheating system 100A or a hot water supply system 10OB. lf the supply water sensor3 or 33 is a surface sensor as shown in Fig. 2d, the heating resistor 8 or 38 can beconnected to the supply water sensor 3 or 33 by clamping, gluing or soldering. Pref-erably, highly heat conductive adhesive material is provided in the joint between theresistors 8 or 38 and the supply water sensor 3 or 33. lf the original supply water sensor 3 or 33 is of a type in which the sensor gauge isinstalled via a hole in the pipe 35 to the inside of the pipe 35, then the original supplywater sensor can be replaced by a sensor that also comprises the heating resistor8 or 38 according to the invention. 13 Figure 3 shows an example of how a load limiting device 6 according to the inven-tion controls the intake of district heating in a building. ln the example of Fig. 3, thecontrol measures taken by the load limiting device 6 according to the invention havesucceeded in keeping the heating load curve 200 below the limit value 5 for thebasic fee. When the load evens out below the limit value 5 for the basic fee, the loadlimiting device 6 according to the invention reduces the load limiting measures pref-erably gradually by reducing the electric current supplied to the heating resistors 8and 38 connected to the supply water sensors 3 and 33. ln the upper part of Fig. 3, a graph represents the district heating load of an exem-plary building in kW as a function of time.

The lower part of Fig. 3 shows the magnitude of limiting measures by a load limitingdevice 6 according to the invention as a function of time, in percentages of the max-imum load limit at different times.

The exemplary limit value 5 (300 kW) for the basic fee in Fig. 3 is the same as in theexample of Fig. 1b. ln the example of Fig. 3, one proactive upper limit 21 is pro-grammed in the load limiting device 6 in the control arrangement according to theinvention; exceeding this limit will trigger load limiting measures by the load limitingdevice 6 according to the invention. Reference 22 represents a proactive lower limit;a value lower than this will start a gradual reduction in the load limiting measures.

Preferably, more load limit values than are shown in Fig. 3 may be utilized in theinvention, between the proactive upper limit 21 and the proactive lower limit 22. Anyexceeding of a load limit value between the above mentioned two limit values andcloser to the proactive upper limit 21 than the previous exceeded load limit value, ispreferably programmed to increase, for example, the electric current supplied to theheating resistors 8 and 38 shown in Fig. 2c, the more, the closer the exceeded loadlimit value is to the proactive upper limit 21. ln this way it is possible to set the tem-perature control device 1 of the building to limit the heating load more swiftly in asituation in which the heating load is either found or foreseen to increase rapidly, forwhatever reason.

In a case where the load limiting device 6 according to the invention ﬁnds that thelimit value 5 for the basic fee set for the building has been exceeded, the load limitingdevice 5 preferably triggers predetermined maximum load limiting measures deﬁnedfor the load limiting device 6. 14 The example of Fig. 3 shows a heating load curve 200 for an exemplary building asa function of time. At a moment of time 201, the heating load exceeds a proactiveupper limit 21 according to the invention. As a result, the load limiting device 6 ac-cording to the invention triggers the load limiting measures. The load limiting device6 is preferably programmed to increase the load limiting measures linearly from themoment of time 201, reference 200a.

The load limiting measures of the load limiting device 6 include, for example in theload limiting arrangement 20B of Fig. 2c, applying the heating resistors 8 and/or 38for heating at least one of the supply water sensors 3 or 33. As a result of the heat-ing, the actual temperature control device 1 of the building receives a correctedtemperature value 3a and/or 33a from the supply water sensor 3 and/or 33. Conse-quently, the temperature control device 1 transmits a new setting to the valve 4 inthe district heating network 10A and/or to the valve 34 in the district heating network10B, for limiting the ﬂow rate of hot water from said district heating network. Thelimitation in the ﬂow rate is preferably the greater, the faster or higher the load peakfound or predicted by the load limiting device 6 according to the invention. ln the example of Fig. 3, the load limiting device 6 according to the invention ﬁndsthat the heating load of the resistor has been sufﬁcient during the load limitingmeasures, whereby the load is lower than the proactive upper limit 21 at a momentof time 202. Thus, the load limiting measures are preferably kept constant at theachieved load limiting level; reference 200b. ln the example of Fig. 3, however, the heating load of the building exceeds the pro-active upper limit 21 according to the invention again at a moment of time 203. Asa result, the load limiting device 6 according to the invention starts to increase theload limiting measures again from the moment of time 203, reference 200c. Theload limiting device 6 is preferably programmed to increase the load limitingmeasures again linearly from the moment of time 203, reference 200c. ln the example of Fig. 3, the load limiting device 6 according to the invention nowfinds that as a result of increasing the load limiting measures further, the load goesdown below the proactive upper limit 21 again at a moment of time 204. Thus, theload limiting measures are preferably kept constant at the level achieved at the mo-ment of time 204; reference 200d. ln the example of Fig. 3, the load limiting device 6 ﬁnds next that the heating loaddrops below the proactive lower limit 22 for the load at a moment of time 205. Thus,the load limiting device 6 preferably decreases the load limiting. The phasing out ofthe load limiting is preferably programmed so that the load limiting device 6 reducesthe load limiting measures linearly, reference 200e. However, after the moment oftime 205, the reduction in the load limiting is preferably slower than the increase inthe load limiting after the moment of time 201 described above. ln the example of Fig. 3, the heating load of the building exceeds the proactive lowerlimit 22 according to the invention again at a moment of time 206. As a result, theload limiting device 6 according to the invention maintains the load limiting levelachieved at the moment of time 206, from the moment of time 206; reference 200f. ln the example of Fig. 3, the heating energy drops the proactive lower limit 22 againat a moment of time 207. Thus, the load limiting measures are gradually reducedagain, preferably at the same rate of reduction, reference 200g, as after the momentof time 205. ln the example of Fig. 3, the heating load of the building no longer exceeds theproactive lower limit 22. As a result, the limiting device 6 according to the inventionstops the load limiting measures at a moment of time 208.

Operating in the district heating control arrangement 20A of Fig. 2b, for example,the load limiting device 6 according to the invention controls the temperature controldevice 1 of the building directly via a communication link 6c, for example by chang-ing the target temperature of the supply water sensors 3 and/or 33 in such a waythat the temperature control device 1 will transmit new settings to the valves 4 and/or34, for reducing the ﬂow rate of district heating water.

Figure 4 shows, as an exemplary ﬂow chart, the main steps in the method accordingto the invention for limiting the district heating load, to be taken by the load limitingdevice 6 according to the invention. The method is utilized for preventing the short-term heating peak load from exceeding a limit value (reference 5 in Fig. 3) for thebasic fee determined for the building. ln step 40, the load limiting device according to the invention, installed in parallelwith the temperature control device 1 controlling the heating of the building, is 16 activated. The activation may be either a one-off measure, whereby the load limitingdevice 6 is continuously active, or an activation in a given cold season.

At the beginning of step 41, the load limiting device 6 is on standby and is ready toreceive a meter pulse 7a transmitted by the district heating meter 7 of the building,representing the thermal energy consumed. The district heating meter 7 transmits ameter pulse 7a whenever a predetermined amount of thermal energy has been con-sumed in the heating system of the building which preferably contains two circulatingwater systems: the heating system 100A and the hot water supply system 100B.The predetermined amount of energy for which the district heating meter 7 of thebuilding transmits a meter pulse 7a may be preferably, for example, 1 kWh or10 kWh. The amount of energy reﬂected by the meter pulse 7a is preferably deter-mined according to the building to be such that several meter pulses 7a are trans-mitted per hour by the district heating meter 7 during a cold heating season. At theend of the step 41 , the load limiting device 6 receives the meter pulse 7a transmittedby the district heating meter 7. ln step 42, the load limiting device 6 computes the thermal load of the building forthe time between the latest received meter pulse 7a and the preceding meter pulse,by dividing the amount of energy indicated by the meter pulse 7a by the time elapsedbetween the receptions of the above mentioned meter pulses. ln step 43, the load limiting device 6 checks whether the ﬁrst proactive upper limit21 according to the invention, conﬁgured to trigger the measures according to theinvention for limiting the heating load, has been exceeded. lf the first proactive upperlimit 21 for the heating load has not been exceeded, the control process returns tostep 41, in which the load limiting device 6 is ready to receive the next meter pulse7a from the district heating meter 7 of the building.

If it is found in step 43 that the proactive upper limit 21 for the heating load has beenexceeded, the load control process according to the invention is started in step 44.Thus, the load limiting device 6 triggers the measures for limiting the district heatingload. The limiting measures include correcting the temperature reading 3a or 33,measured by the supply water sensor 3 or 33 of at least one of the circulating watersystems in the building, upwards. The correction in the temperature measurementmay be made preferably by heating (references 9 and/or 39) the supply water sen-sor 3 or 33 by means of heating resistors 8 and/or 38. 17 ln a preferred embodiment of the invention, the target temperature for the districtheating temperature control device 1 of the building is corrected via one or morecontrol inputs 6c in the temperature control device 1.

Step 45, in which the load limiting arrangement according to the invention is in op-eration, is similar to step 41. At the beginning of step 45, the load limiting device 6is on standby and is ready to receive the next meter pulse 7a from the district heatingmeter 7 of the building. At the end of step 45, the load limiting device 6 receives anew meter pulse 7a from the district heating meter 7. ln step 46, the load limiting device 6 computes the average load of thermal energyfor the time between the latest meter pulse 7a received during the load limitingmeasures, and the preceding meter pulse, by dividing the amount of energy of themeter pulse 7a by the time elapsed between said meter pulses.

The next steps 47a and 47b are comparative steps for ﬁnding out the current trendin the district heating load of the building. ln step 47a, the load limiting device 6 detects whether the load value is below theproactive upper limit 21 which is between the limit value 5 used for determining thebasic fee for district heating, and the proactive lower limit 22. lf it is detected in step 47a that the load value is not below said proactive upper limit21, the control process will retum to step 44. Thus, at the beginning of the step, theelectric current supplied to the heating resistors 8 and/or 38 of at least one supplywater sensor 3 and/or 33 is increased, for raising the temperature measurementvalue 3a and/or 33a for supply water. After this, in step 44, the next meter pulse 7ais waited for. lf it is found in step 47a that the load value is below said proactive upper limit 21,the control process will proceed to the next comparative step 47b. ln the comparative step 47b, the measured value for the average load is compared,as in step 47a, to ﬁnd out whether the measured average load has dropped belowthe proactive lower limit 22. lf it is found in step 47b that the load value has not dropped below said proactivelower limit 22 -the conclusion alternative "No" - the control process will move on to 18 step 48 in which the load limiting measures are continued with the existing settingsfor the load limiting, and the load limiting process will return to step 44. lf it is found in step 47b that the load value has dropped below said second limitvalue - the conclusion alternative "Yes" - the control process will move on tostep 49. ln step 49, the load limiting device 6 reduces the load limiting. After the conclusionhas been made, the load limiting device 6 will reduce the load limiting, for example,by reducing the electric current supplied to the heating resistors 8 and/or 38 of thesupply water meters 3 and/or 33. After this, the load limiting device 6 according tothe invention will move on to step 44, to wait for the next meter pulse 7a.

After this, the four control loops 41 to 43; 44 to 47a; and 47a, 47b, 48, 44; or 47b,49, 44 are repeated until the average district heating load of the building is reducedbelow the proactive upper limit 21, preferably permanently. When this situation isconﬁrmed by the load limiting device 6, it ceases the load limiting measures. As aresult, the intake of thermal energy in the building will be controlled by the tempera-ture control device 1 for the heating load of the building.

All the adjustment process steps presented in Fig. 4 may be implemented by com-puter program commands which are run in a suitable universal or special processor.The computer program commands may be stored on a computer readable medium,such as a data disc or a memory, from which the processor of the load limiting device6 may retrieve said computer program commands for execution. The references tothe computer readable media may also include, for example, special components,such as programmable USB ﬂash memories, Iogic networks (FPLA), client-speciﬁcintegrated circuits (ASIC), and signal processors (DSP).

Figure 5 shows a preferred embodiment, showing main functional components ofthe load limiting device 6 according to the invention.

The load limiting device 6 may preferably comprise an energy source 63, which maybe a power supply connected to an alternating current network, an accumulator, ora battery. lf the power source 63 is a battery, it is preferably chargeable. The electriccomponents included in the load limiting device 6 are supplied with electric energyfrom this power source 63. 19 The load limiting device 6 comprises a central processor unit 61 (CPU) with a com-munication link to a memory 62. The memory 62 is used for storing the control al-gorithms/computer software and the limit values used for the control needed for run-ning the load control process according to the invention. All the average load valuescomputed by the load limiting device 6, and the data on the load limiting measurestaken, with time stamps, are also stored in the memory 62, at least temporarily.

Preferably, three inputs are connected to the processor 61 of the load limiting device6, via which inputs the load limiting device 6 has an effect on the measures takenby the actual temperature control device 1 of the building for controlling the use ofdistrict heating energy.

Via the input 65 limiting the heating, the load control device 6 supplies electric powerto the heating resistor 8 coupled to the supply water sensor 3 of the heating system100A when the load limiting device 6 has detected a need in limiting the load. Themagnitude of electric power supplied to the heating resistor is determined by theload limiting device 6 on the basis of the need for limiting the load. The higher theheating power supplied to the heating resistor, the more swiftly and efﬁciently thetemperature measurement value of the supply water sensor 3 is increased by theload limiting device 6. By increasing the temperature measurement value of the sup-ply water sensor 3, the load limiting device 6 has an effect on the operation of thetemperature control device 1 of the building. The electric power to be supplied to theheating resistor 8 can be preferably controlled by changing the supply voltage of theheating resistor 8. Alternatively, it is possible to apply time ratio control, whereby thesupply voltage of the heating resistor 8 is a constant voltage but the constant supplyvoltage is broken on the basis of the need for control.

Via the input 66 for limiting the hot water supply, the load limiting device 6 preferablysupplies electric power to the heating resistor 38 coupled to the supply water sensor33 of the hot water supply system 100A as well, after the load limiting device 6 hasfound it necessary to apply load limiting in the supply water system 100B, too.

Via the control output 67, the load control device 6 controls the actual temperaturecontrol device 1 of the building, preferably directly. The control message to the tem-perature control device 1 may be, for example, a 0 to 10 V voltage message or a 4to 20 mA current message, depending on the type of the temperature control device1. By changing the voltage or the current, the load limiting device 1 according to theinvention controls the operation of the actual temperature control device 1 of the building to restrict the energy intake from the district heating network by controllingthe functional settings of the valves 4 and/or 34 in the district heating networks 10Aand 10B.

Preferably, the load limiting device 6 may also comprise a user interface 68. Theuser interface preferably comprises a display unit and a suitable keypad for control-ling the functions of the load limiting device 6. Preferably, the load limiting device 6according to the invention may also comprise a wired or wireless data network con-nection 69 with suitable inputs and outputs for remote monitoring and remote controlof the district heating load of the building.

Some preferred embodiments of the load limiting device, system arrangement, loadlimiting method, and computer program product to be utilized in the use of heatingenergy according to the invention have been described above. The invention is notlimited to the solutions described above, but the inventive idea may be applied in anumber of ways within the scope of the claims.

Claims

21 Claims

1. A method for limiting the heating load of a building, the method comprising - measuring the temperature with an outdoor thermometer (2), - measuring the temperature of water supplied to at least one circulating water sys-tem (100A, 100b) of the building by a supply water sensor (3, 33), - receiving the temperature measurement (2a) from the thermometer (2) and thetemperature measurement (3a, 33a) from the supply water sensor (3, 33) by a tem-perature control device (1) of the building, and - controlling at least one valve (4, 34) in the district heating network (10A, 10B) bythe temperature control device (1) of the building on the basis of the outdoor tem-perature (2a) and the temperature measurement results (3, 3a) of the supply watersensor (3, 33), for maintaining the indoor temperature in the building;characterized in that the method further applies a power limiting device (6) for - receiving (41) meter pulses (7a) reﬂecting the heating energy consumption, fromthe energy meter (7) of the building to the load limiting device (6); - computing (42) the average heating load of the building between two successivemeter pulses, by the load limiting device (6); - comparing (43) the computed average heating load with a proactive upper limit(21 ) set for the heating load, by the load limiting device (6), and if the proactive upperlimit (21) set for the heating load has been exceeded, -triggering (44) measures for restricting at least one valve (4, 34) in the districtheating network (10A, 10B), for reducing the heating load of the building.

2. The method according to claim 1 for limiting the heating load, characterizedin that for changing the setting of the valve (4, 34) in the district heating network(10A, 10B), the supply water sensor (3, 33) of at least one circulating water system(100A, 100B) is heated by a heating resistor (8, 38).

3. The method according to claim 2 for limiting the heating load, characterizedin that, when limiting the heating load, the method comprises - receiving (45) meter pulses (7a) transmitted by an energy meter (7), - computing (46) the average heating load of the building between each receivedmeter pulse and the preceding meter pulse, by the load limiting device (6); - comparing (47a) the computed average heating load with a proactive upper limit(21) set for the heating load, by the load limiting device (6), and if the load value isnot below the proactive upper limit (21 ) for the heating load set, setting the measuresfor limiting the heating load constant by maintaining the electric power supplied to 22 at least one heating resistor (8, 38) heating the supply water sensor (3, 33) of atleast one circulating water system (100A, 100B).

4. The method according to claim 3 for limiting the heating load of a building,characterized in that, if the load value is below the proactive upper limit (21) set forthe heating load, the method comprises - comparing (47b) the computed average heating load with a proactive lower limit(22) also set forthe heating load, by the load limiting device (6), and if the load valueis below the proactive lower limit (22) set for the heating load, - starting (49) measures for phasing out the limiting of the load of at least one districtheating network (10A, 10B) by reducing the electric current supplied to at least oneheating resistor (8, 38) heating the supply water sensor (3, 33) in the circulatingwater system (100A, 100B).

5. The method according to claim 4 for limiting the heating load of a building,characterized in that, if the load value is not below the proactive lower limit (22) forthe heating load, the method comprises continuing the load limiting with the currentload limiting settings.

6. The method according to claim 1 for limiting the heating load of a building,characterized in that the method comprises reducing the setting of the valve (4, 34)of at least one district heating network (10A, 10B) by transmitting correction datareducing the target temperature of the supply water sensor (3, 33), to the tempera-ture control device (1) of the building.

7. The method according to any of the claims 1 to 6 for limiting the heating load,characterized in that the circulating water system, whose heating load is being lim-ited, is either a heating system (100A) or a hot water supply system (1 OOB).

8. An arrangement (10, 20, 20A, 20b) for limiting the heating load of a building,comprising - an outdoor thermometer (2) for measuring the outdoor temperature, - a supply water sensor (3, 33) for measuring the temperature of water supplied toat least one water supply system (100A, 100B), - a temperature control device (1) of a building, the thermometer (2) and the supplywater sensor (3, 33) being coupled to it; and -the temperature control device (1) being conﬁgured to control the valve (4, 34) ofat least one district heating network (1 OA, 10B) for controlling the temperature in the 23 building, on the basis of the outdoor temperature and the temperature measurementdata from the supply water sensor (3, 33), for maintaining the indoor temperature inthe building; characterized in that the arrangement for limiting the heating load further comprisesa load limiting device (6) which is conﬁgured -to receive (41) meter pulses (7a) reﬂecting the heating energy consumption, fromthe energy meter (7) of the building to the load limiting device (6); -to compute (42) the average heating load of the building between two successivemeter pulses, by the load limiting device (6); -to compare (43) the computed average heating load with a proactive upper limit(21 ) set for the heating load, by the load limiting device (6), and if the proactive upperlimit (21) set for the heating load has been exceeded, - to trigger (44) measures for restricting at least one valve (4, 34) in the district heat-ing network (10A, 10B), for reducing the heating load of the building.

9. The arrangement (10, 20, 20A, 20B) according to claim 8 for limiting the heat-ing load, characterized in that for changing the setting of the valve (4, 34) of thedistrict heating network (10A, 10B), the supply water sensor (3, 33) of at least onecirculating water system (100A, 100B) is conﬁgured to be heated by a heating re-sistor (8, 38).

10. The arrangement (10, 20, 20A, 20B) according to claim 9 for limiting the heat-ing load, characterized in that upon limiting the heating load, the arrangement forlimiting the heating load is conﬁgured -to receive (45) meter pulses (7a) transmitted by an energy meter (7), -to compute (46) the average heating load consumed in the building between eachreceived meter pulse and the preceding meter pulse, by the load limiting device (6);-to compare (47a), by the load limiting device (6), the computed average heatingload with a proactive upper limit (21) set for the heating load, and if the load valueis not below the proactive upper limit (21) for the heating load set, to set themeasures for limiting the heating load constant by maintaining the electric powersupplied to at least one electric resistor (8, 38) heating the supply water sensor (3,33) in at least one circulating water system (100A, 100B).

11. The arrangement according to claim 12 for limiting the heating load, charac-terized in that if the load value is below the proactive upper limit (21) for the heatingload, the arrangement is further conﬁgured 24 -to compare (43) the computed average heating load with a proactive lower limit(22) set for the heating load, by the load limiting device (6), and if the load value isbelow the proactive lower limit (22) set for the heating load, - to start (49) measures for phasing out the limiting of the load of at least one districtheating network (1OA, 10B) by reducing the electric current supplied to at least oneelectric resistor (8, 38) heating the supply water sensor (3, 33) in the circulatingwater system (100A, 100B).

12. The arrangement according to claim 8, 9, 10, or 11 for limiting the heating load,characterized in that the water supply system, whose intake of thermal energy isbeing limited, is either a heating system (100A) or a hot water supply system (1 OOB).

13. A load limiting device (6) for limiting the district heating load of a building, char-acterized in that the load limiting device (6) comprises means -for receiving (41) meter pulses (7a) reﬂecting the heating energy consumption,coming from the energy meter (7) of the building to the load limiting device (6),-for computing (42) the average heating load of the building between two succes-sive meter pulses, -for comparing (43) the computed average heating load with a proactive upper limit(21) set for the heating load, and if the proactive upper limit (21) set for the heatingload has been exceeded, - for triggering (44) measures for restricting at least one valve (4, 34) in the districtheating network (1OA, 10B), for reducing the heating load of the building.

14. The load limiting device according to claim 13, characterized in that for chang-ing the setting of the valve (4, 34) of the district heating network (1OA, 10B), it com-prises means conﬁgured to heat the supply water sensor (3, 33) of at least onecirculating water system (100A, 100B) by a heating resistor (8, 38).

15. The load limiting device according to claim 14, characterized in that the loadlimiting device further comprises, for limiting the heating load, means -for comparing (47a) the computed average heating load with a proactive upperlimit (21) set for the heating load, and if the load value is not below the proactiveupper limit (21) set for the heating load, -for setting the measures for limiting the heating load constant, by maintaining theelectric power constant in the heating resistor (8, 38) heating the supply water sen-sor (3, 33) of at least one circulating water system (100A, 100B).

16. The load limiting device according to claim 15, characterized in that if the loadvalue is below the proactive upper limit (21) for the heating load, the device furthercomprises means conﬁgured -to compare (43) the computed average heating load with a proactive lower limit(22) set for the heating load, and if the load value is below the proactive lower limit(22) set for the heating load, -to start (49) measures for phasing out the limiting of the load of at least one districtheating network (10A, 10B) by reducing the electric current supplied to the heatingresistor (8, 38) heating the supply water sensor (3, 33) of at least one circulatingwater system (100A, 100B).

17. The load limiting device according to claim 13, characterized in that it com-prises means for reducing the setting of the valve (4, 34) of at least one districtheating network (10A, 10B) by transmitting (6b) data correcting the target tempera-ture of the supply water sensor (3, 33) of at least one circulating water system, tothe temperature control device (1) controlling the heating load of the building.

18. A computer program product, characterized in that it comprises computer pro-gram code means stored on a computer readable storage medium, the code meansbeing conﬁgured to execute all the steps of the load limiting method deﬁned in oneof claims 1 to 6 when said computer program is run in a processor of a data pro-cessing device.