[0002] The invention relates to heat distribution systems or in gen- eral to systems distributing flowing medium, in which through a distribution sys- tem, medium flows of a predetermined size are distributed to several points of use for heating, cooling or drying rooms, production processes or some other points of use, or for some other purpose of use. Examples of such systems include heating systems of housing blocks, factories, business and public buildings and other large buildings that distribute heating water often to hun- dreds of heat consuming devices such as radiators, convectors, radiation roofs, air-conditioning and wind chamber machines, etc. by means of an ex- tensive and complex piping network. Even the heating networks of small build- ings, for instance single-family houses, often have nearly 20 heat-consuming devices connected to them, to all of which at least a design water flow should be conducted so as to reach a design room temperature in a dimensioning situation. The water flows should, however, not be bigger than designed, be- cause this causes unnecessary pumping costs and easily leads to an unnec- essarily high room temperature and thus to unnecessary heat consumption.

[0003] In earlier systems, when the heating need was small, a smallish thermostat valve or some other room temperature adjusting device could easily end up outside its adjusting range and start to operate with the open/closed principle, which easily leads to fluctuation in the room tempera- ture, thus reducing comfort. In addition, the devices wear unnecessarily. Incor- rect water flows also cause other disadvantages. In buildings connected to the district-heating network, for instance, too large a water flow causes an unnec- essarily high connection and basic fee to the user of the building. A high water flow leads to reduced cooling of water in a building, thus increasing the energy bill. Reduced cooling lowers the heat convection power of the district heating network, increases pumping costs and heat losses, and reduces the efficiency of a power plant and the electric supply per fuel unit. This naturally leads to an

increase in the environmental load caused by increased emission.

[0004] Because of the drawbacks described above by way of ex- ample and many other drawbacks, heating systems are generally built in such a manner that a flow control device is placed in the pipe leading to each site of use; usually this is a single-control valve, by means of which the water flow at the site can be adjusted to plan in a dimensioning situation. To achieve a suffi- cient adjustment margin, the pressure of the system pump is made higher than the pressure loss calculations require.

[0005] When the system is then adjusted, problems occur immedi- ately. The water flow of the first selected site of use is easy to adjust to be cor- rect. Since the water flow of a second site of use is usually adjusted to be smaller, the water flow of the entire system also decreases, whereby pressure in the sites of use increases, because when the flow decreases, the flow resis- tances decrease in proportion to the water flow squared. Generally, when the water flow decreases, the pressure generated by the pump also increases.

When the pressure increases in the network, the water flow of the site of use adjusted first increases, i. e. it is no longer according to plan. When the adjust- ment is continued in the next points of use, the error increases almost without exception. Even after adjusting ten sites of use, the water flow of the site of use adjusted first usually differs already considerably from plan. It has been shown that the basic control of a large building comprising dozens or hundreds of sites of use would even with moderate accuracy require repeating the basic control numerous times, take a long time and be unreasonably expensive.

[0006] An attempt to improve the situation has been made by divid- ing large systems into separate lines that provide heat to a smallish number of sites of use and that each have separate line control valves. This way, the wa- ter flows can be adjusted to be correct for one line at a time and finally the line control valves can be used to adjust the total water flows of the lines to be cor- rect, whereby the water flows of the sites of use adjust themselves to the cor- rect level. The line control valves are large in size and thus often difficult to install in place. Above all, line control valves considerably increase the invest- ment costs of a heating system and add to the pressure loss of the system.

The basic control of the line is further slow and arduous, requires professional skill and generates significant costs. Therefore, the quality of the basic control is often sacrificed both for schduling and cost reasons, which increases the consumption of heating and electric energy and reduces comfort in the prem-

ises being heated. This is why it has been noted in energy inspections of build- ings and several conducted studies that the average temperature of buildings is very often 1 to 3 degrees too high due to inadequate basic control, the varia- tion of room temperatures is 3 to 6 degrees too high, the consumption of heat- ing energy is 10 to 30% too high and the consumption of electric energy used for pumping is 20 to 40% too high. After a corrective basic control, the meas- urements generally show a reduction of room temperature variation to below two degrees, a decrease in the average temperature of the building and a de- crease in energy consumption as described above. Checking the basic control is almost always the first routine action to be taken in an energy inspection.

Increase in comfort due to a better basic control can usually be noted from the fact that no more complaints are received concerning room temperatures or there are substantially fewer complaints than before. Savings in cooling and an increase in comfort are usually even bigger than described above. Recently conducted studies show that improved heating conditions clearly improve work efficiency and reduce absences. Even a small improvement in these provides a greater saving than the costs of an expensive basic control.

[0007] The fact that the basic control of heating and cooling sys- tems of buildings is in a poor state can also be explained by the altered use of the buildings, especially in business and public buildings. Buildings are no longer used in the same manner or even for the same purpose for decades, and their use most often changes considerably within a few years. Due to the change in use, heating and cooling devices are added or removed, the need for heating and cooling in different parts of the building may change consid- erably, etc. Basic control is often not done, especially when several smallish changes are made one after the other. This results in high-energy consumption and reduced comfort and work efficiency.

[0008] The high importance of basic control has generally been un- derstood and several methods for facilitating it have been developed. The drawback of these known methods is, however, their complexity and arduous- ness that increase costs.

[0009] It is an object of the invention to provide a method and appa- ratus, by means of which the drawbacks of the prior art can be eliminated. This is achieved by the present invention. The method of the invention is character- ized in that the sites to be controlled or some of them are for the time of the control equipped with a device measuring a quantity indicating a medium flow

and that the measuring results are transmitted to a calculating unit through a data transmission network. The apparatus of the invention is, in turn, characterized in that the sites to be controlled or some of them are for the time of the control equipped with a device measuring a quantity indicating a medium flow and that the measuring results are arranged to be transmitted to a calcu- lating unit through a data transmission network.

[0010] Above all, the invention provides the advantage that the method is easy and accurate, the adjustment can, if necessary, be done by one person only even in a large plant, and the pressure loss and pumping power are substantially smaller than in the known methods. When using the most advanced applications of the invention, it is not necessary to allocate time for the basic control, which at the final stage of the building work and while the building schedules continue to become tighter may have a very high financial significance. The solution of the invention can be implemented entirely without separate single-control valves. Twin valves are also not needed, which further reduces costs. It is of even more importance that the valves cause no extra pressure loss, which decreases the size of the required pump and electric mo- tor, nor will there be any extra operating costs due to increased electricity con- sumption. The adjustability of the system when the required heating efficiency varies also improves, because the pressure generated by the pump is lower.

The invention also has many other advantages that will be described in greater detail in the detailed description of the invention.

[0011] In the following, the invention will be described in greater de- tail by means of the examples shown in the attached drawing in which Figure 1 shows a single control principle of the prior art, Figure 2 shows a heating system built according to the prior art, Figure 3 shows the principle of application of the method of the in- vention, Figure 4 shows a heating system built according to the method of the invention, Figure 5 shows an advanced form of a heating system built accord- ing to the method of the invention.

[0012] Figures 1 and 2 show a general view of a method for per- forming basic control by means of a twin valve and a reference valve, the method being earlier perhaps the most commonly used one. Figure 1 shows the principle of such a method and Figure 2 correspondingly the entire system.

[0013] Figure 1 shows heat-consuming devices 2,3,4,5 and their single-control valves 6,7,8,9. In addition to these, the method requires an extra twin valve 1 fixedly mounted to a main line 11 and a water flow measur- ing device shown as a pressure difference gauge 10 in Figure 1, which can be a movable gauge and which monitors the pressure difference of valve 9, se- lected as the reference valve, and thus also the water flow.

[0014] The basic control is performed in such a manner that the wa- ter flow of a consuming device 5 is adjusted to plan by valve 9 selected as the reference valve. After this, the water flow of the next consuming device is ad- justed, for instance in device 4 using valve 8. When valve 8 is adjusted, the pressure of the system changes and thus also the water flow of device 5. In the method, the pressure of the system and the water flow of device 5 are cor- rected by adjusting twin valve 1. This is repeated when adjusting the water flow of consuming devices 2 and 3 to be correct.

[0015] Figure 2 shows how the method is applied to a more exten- sive system that is divided into several subsystems of different levels. Figure 2 shows an arrangement having several subsystems according to Figure 1. Fig- ure 2 uses the same reference numerals as Figure 1 in the corresponding sec- tions. The basic control of the first subsystem of Figure 2, which is marked with the reference numerals corresponding to Figure 1, is performed as described in connection with Figure 1.

[0016] When moving on to adjust the next subsystem of Figure 2, the tasks of the valves need to be changed. Twin valve 1 of the first subsystem is now selected as the reference valve and its flow rate is kept constant by ad- justing twin valve 14 common to the subsystems. In principle, it is of course also possible to monitor the original reference valve 9. The adjustment of the subsystems is now done by means of twin valves 12 or 13 and the reference valve, keeping, however, the flow rate of the first subsystem at the adjusted value by means of reference valve 9 or alternatively valve 1 and twin valve 14.

It is thus necessary to simultaneously monitor the flow rates of four valves.

[0017] In largish buildings, there are often so many devices that to keep the number of the points of use to be adjusted in the subsystems reason- able, yet a third system level is required, the subsystem twin valves of which that correspond to twin valve 14 are valves 15 and 16. The subsystems can in principle be similar to the subsystem shown in Figure 2, the twin valve of which is valve 14, but they are not significant to understanding the principle and are

not shown in Figure 2 for the sake of simplicity. For adjusting the subsystems, a next-level twin valve 17 is again needed. The earlier twin valve 14 can serve as the reference valve, or in fact any valve of the subsystem that valve 14 serves when the subsystems are adjusted that have valves 15 and 16 as their twin valves.

[0018] The fluid flow of the entire system is achieved by means of a pump 18 and the temperature of its output water is adjusted correct by means of a shunt valve 19. Figure 2 could show a typical radiator network of a largish building. Buildings usually have different types of apparatuses, such as air- conditioning machines, convectors, wind chamber machines, etc., having dif- fering pressure losses, output water temperatures, operating times, etc. This is why the heating systems of buildings usually comprise several subsystems having their own pumps and/or shunt valves, in Figure 2 pumps 20 and 21 and valves 22 and 23. In principle, the same problems exist in the basic control of all of them.

[0019] The known method described above and other similar known methods have many weaknesses. The basic control can be performed in one control cycle, but during the control, more than one valve needs to be moni- tored, or in fact the flow rates of the subsystems or sites of use that the valves are to adjust, and in practice, it usually requires that at least two persons par- ticipate in the control and perform the adjustments simultaneously keeping contact through a wireless telephone, for instance. The performance of simul- taneous adjustments requires great professional skill and experience so as not to take an unreasonable amount of time. For a fast control, three persons are needed, one to adjust the water flow of the desired site of use or subsystem and one to monitor the reference valve and to give instructions to the third per- son who adjusts the twin valve. In any case, the work is slow and the costs high.

[0020] As noted above, an extra control valve, a twin valve, is re- quired in the method for each subsystem. In addition to this already causing considerable costs per se at each building stage of the system, the valves also continuously consume electricity as pumping power during use firstly because the valves per se have a significant pressure loss, according to recommenda- tions at least 5 kPa fully opened. In addition to this, it is recommended to leave a certain adjustment margin for each twin valve generally in such a manner that the pre-adjustment value is in the range of 75 to 90% of the Kv value of a

fully opened valve, i. e. the valve is roughly only 75 to 90% open with respect to the fully open position. The pressure loss caused by this naturally varies depending on for instance the valve type and dimensions, but, for instance as in the application of Figure 2, when there are three twin valves in series, their pressure loss is even in the most advantageous case at least 40% of the pres- sure loss of the entire system, often as great as the pressure loss of the entire system being adjusted. The basic control of the method thus often doubles the electricity consumption of pumping. This is natural, since the entire method is based on throttling the flow with valves. It should, however, be remembered that in a poorly controlled system, the consumption is even considerably bigger than this.

[0021] The method described above requires that the control be started in the site of use producing the highest total system resistance, i. e. from the site of use, according to which for instance the system pump is de- signed. In practice, this has proven to be difficult especially in systems with long distances, high flow rates and various devices. If the above-mentioned adjustment margin is not left during pre-adjustment, it may occur that a flow rate according to plan is not reached even though the single-control valve is fully opened. The adjustment then needs to be started from the beginning or at least a large part of the adjustment needs to be redone.

[0022] The basic idea of the control method described above, i. e. keeping the flow rate in the reference valve according plan at all times, makes it possible to perform the basic control as a one-time job without several ad- justment cycles, but it is at the same time its greatest weakness that results in all the above-mentioned problems. However, the above-mentioned known method enables a systematic performance of the control and thus also a se- cure final result. Experience also shows that the method can be taught in a reasonable time and at reasonable costs in other ways than through trial and error. Due to these reasons and in spite of the above-mentioned weaknesses, this method is the most commonly used method at the moment.

[0023] The field also knows what is known as a relative method, the basic idea of which is that the first valve to be adjusted is considered the refer- ence valve that is not touched during the adjustment of other valves, but whose flow rate need not be kept constant during the adjustment of the other valves and is allowed to change.

[0024] The adjustment is done in such a manner that the ratio of the

flow rate of both the valve to be adjusted and the reference valve prevailing at the time of the adjustment to the flow rate according to plan is adjusted to be the same. This is done with every valve. When all the valves have been ad- justed, the flow rate of the reference valve is adjusted to plan, i. e. the ratio be- tween the reference valve flow rate and the flow rate according to plan is ad- justed to one by altering the rotation rate of the pump through adjusting the single-control valve of the entire system or through some other manner. When the ration between the flow rate of all the valves and the reference valve and the design flow rate is adjusted to be the same, the ratio of the flow rates in all the other valves also becomes one, thus providing design water flow in all sites of use.

[0025] This means that only two valves, the valve to be adjusted and the reference valve, need to be monitored during the adjustment. The ad- justment is done by changing the position of this one valve only, thus making the adjustment faster and more accurate than in a twin valve method, in which two valves are adjusted at the same time while simultaneously maintaining a constant medium flow in a third valve. This also means lower costs and less time used for the adjustment.

[0026] It has, however, proven difficult to apply this, in theory excel- lent method to practice. Firstly, the adjustment should be started from the site of use, having the highest pressure loss. Pressure loss can be determined by calculation, but practice has shown that the result is extremely unsure. Thus, the instructions require measuring the flow rates before starting the adjust- ment, at least on the main lines and the sites of use that are calculated to have the highest pressure loss. This naturally increases costs and slows down work.

[0027] Even the measurement is often difficult. When starting the adjustment, all control valves are open. This means that the medium flow is led to the parts of the system, where flow resistance is low, and it correspondingly decreases in the parts, where the resistance is high, often to such extent that it cannot be measured at sufficient accuracy. The instructions then advice to start the adjustment from the parts of the system that can be measured and to adjust them first, whereby the medium flow in the other parts increases and can thereafter be measured and adjusted. As the instructions note, an extra pressure loss then remains in the system, the size of which depends on how well the adjustment values of the valve adjusted first have been estimated. The use of the method has proven to require so high a professional skill, the costs

so much higher and the time required for the adjustment so much longer in practice and the final result of the adjustment so often a failure that the method is seldom used.

[0028] The basic idea of the invention is that the sites to be adjusted or some of them are equipped with a device measuring a quantity indicating a medium flow, usually pressure loss, that is connected or can be connected to a data transmission network. This can be done for the time of the basic control or in a modern building, preferably in a fixed manner. The data transmission net- work can be any network known per se, such as an ordinary landline network, optical network, wireless network in which information is transmitted wirelessly, etc. Information is transmitted through the network to a calculation unit which, from electric flow pressure readings or other readings indicating water flow, continuously or in response to a calculation command calculates the ratio be- tween the design water flow and the momentary water flow and transmits it for instance as an electric message of an ordinary wireless telephone through an information network of the building or in any other manner known per se to the receiver of the person performing the adjustment. This way, the person per- forming the adjustment always has information on the ratio of the momentary and design water flow between the reference valve and the valve being ad- justed, which means that when using the relative basic control method, the control can be performed by one person only. The method can naturally also be used when performing adjustment by means of twin valves, for instance, in which case the calculation unit calculates water flows instead of the ratio of the water flows, or in connection with any other control method known per se. The advantages of the invention are, however, greatest in connection with the rela- tive control method.

[0029] At its simplest, the apparatus can comprise only two measur- ing devices, one at the reference valve and one at the site being adjusted, if the reference valve can be defined with certainty. There should, however, also be enough movable measuring devices so as to define the reference valve with certainty and to adjust it with sufficient accuracy. In general, it can be said that the highest number of devices are required in extensive, complex systems having many parts with different pressure losses.

[0030] It should be remembered that any device is suitable as the measuring device that measures a quantity indicating water flow with sufficient accuracy. In most sites of use, the heating need varies, which is why a control

valve is required, the effect of which to water flow must be known with suffi- cient accuracy at least for the basic control and the pressure loss of which must be designed fairly high to allow it to serve as a control device. The meas- uring device can in most cases be just a sensor. Instead of the control valve, it is of course possible to select any device, the pressure loss of which is suffi- ciently high and the properties of which are known sufficiently accurately.

[0031] Using the invention, it is possible to perform the basic control even without separate single-control valves, if the sites of use are equipped with settable control valves and if the system is designed and built to be per- fectly balanced. After the basic control, the valves or other control devices are solely given a maximum opening value according to the basic control position or nominal current.

[0032] Today, a practice is becoming common, according to which pumps are equipped with frequency converters for adjusting the rotation rate of the pumps. This way, it is very easy to correct the water flow of a reference valve and the entire heating system after the basic control and to make the plant easily controllable by altering the rotation rate of the pump when the heating need changes.

[0033] If the building is equipped with a centralized data collection and/or control system, as is very often the case in largish new buildings today, it is possible to perform the basic control from a control room by guiding the control valves or other control devices to a position, in which the design flow is achieved, and by locking their maximum position to this. In future, this will have a great significance as new data transmission methods, such as the LON sys- tem, become general. Such systems will probably appear in all largish build- ings already in the next few years, and they will probably become common to detached houses, too. The basic control can naturally also be performed from the control room with separate single-control valves, if they are motor-operated and if the pressure difference or other quantity indicating water flow can be read in the control room.

[0034] In principle, and apparently in simple plants already in prac- tice, it is possible to make a heating system perform the basic control by itself by programming the required measuring and control action to the control cen- tre of the heating system. In such a case, no time or only very little time need to be allocated for the basic control in the building schedule. The required fixed measuring devices naturally cause additional costs. It has, however, been

shown that they are required in any case, if the systems are to be used effi- ciently with respect to energy. Clear proof also exists that they will pay them- selves back in terms of reduced energy consumption relatively quickly. Im- proved comfort and work efficiency should naturally be counted as additional benefits.

[0035] This also has a great significance when aiming at a flexible use of a building. Today, buildings are not designed for a given use for the next thirty years, but the degree of use, purpose of use and heating load of a building may vary yearly. In the manner described above, it is possible to quickly alter the basic control of the heating and cooling systems of a building according to the changed need.

[0036] The invention makes possible to have even more advanced systems. The water flows in the heating and cooling of buildings in particular may during a given season in different parts of the building vary in different ways due to solar radiation, various times of use, load alternatives and many other reasons. By means of the invention, it is possible to program different basic controls for different operating situations. This way, it is possible to adapt the heating, ventilation, cooling and other systems of the building to operate as optimally as possible both with respect to each other and the thermal load.

This provides both a considerable energy saving and an essential improve- ment in comfort and work efficiency in premises served by these technical sys- tems.

[0037] Figure 3 shows the basic principle of the invention. The solu- tion of Figure 3 no longer has the separate basic control valves shown in Fig- ure 1, but the basic control is performed using settable control valves 36,37, 38,39. Valve 39 is selected as the reference valve, the water flow of which is monitored by means of a pressure gauge 40. The water flow of point of use 35 is first adjusted correct by guiding control valve 39 to a correct position and by locking its maximum opening to this position. Next, the water flow of site of use 34, for instance, is adjusted by means of control valve 38 so that the ratio of the water flow to the design water flow is the same as the ratio of the altered water flow to the design water flow of site of use 35, when valve 38 of site of use 35 is adjusted. When the water flow ratios are the same in both sites of use, the maximum opening of valve 38 is locked to this position. The water flows of sites of use 32 and 33 are adjusted in the same manner. Finally, valve 31 is used to correct the water flow of site of use 35, whereby the water flows

of all sites of use correct themselves. Valve 31 is not monitored during the con- trol. It is only used at the end to correct the water flow of site of use 35 to be according to plan.

[0038] The control of a full system according to Figure 4 is in princi- ple done as described above in connection with Figure 3. When the water flows of the first subsystem have been adjusted correct with valves 36,37,38 and 39 and valve 31, while valve 39, for instance, serves as the reference valve, the next subsystem is adjusted using valve 39, or preferably maybe valve 31, as the reference valve. Valves 41 and 42 are only needed for balanc- ing the system, if pressure losses in different subsystems are considerably dif- ferent, so as to make the control valves operate within a good adjustment range. When the subsystems shown in Figure 4 have been adjusted, valve 43 is used to adjust the water flow of valve 31 or 39 correct, after which each site of use has the correct water flow. The same is done in the next-level subsys- tems and finally, valve 44 is used to adjust the water flow of the entire system in such a manner that valve 39,31 or 43 has the correct water flow depending on which valve was used as the reference valve. Valves 31,41,42,45,46 and 43 are not twin valves, but only used to balance the different pressure losses of the different parts of the system so as to make the control valves operate within a good adjustment range.

[0039] The system in Figure 5 is a more advanced form of the sys- tem of Figure 4. Pump 21 is equipped with rotation rate control, as are pumps 20 and 18. The water flow of the entire system, or in fact that of the reference valve, is adjusted correct by adjusting the rotation rate of pump 18, so valve 44 shown in the embodiment of Figure 4 is not needed. Figure 5 also does not have valves 31 and 43 of Figure 4. It is assumed that the flow resistance of the subsystems that these valves serve is so much greater than in the other subsystems that valves 41,42,45 and 46 are always closed to some extent.

[0040] A system of this kind can be made perform the basic control "on its own", if it is equipped with devices for measuring water flow, pressure difference or some other quantity indicating water flow and with telecommuni- cations connections to a data processing device. In it, the basic control can easily be changed when thermal load, the use or purpose of use of the prem- ises or some other factor affecting the basic control changes, it is also possible to improve the operation of the system, save energy and achieve all the other advantages described above.

[0041] Above, the system has been examined by way of example as applied to heating systems in buildings. Within the scope of the claims, it can naturally be applied to any system, in which predetermined medium flows need to be guided to several points of use, such as cooling systems or indus- trial processes, such as dust removal systems, drying systems, heat recovery and air-conditioning systems, etc. The connections shown in the figures are only examples of the application options of the invention. All piping and other connections known per se and the known apparatuses used in them belong naturally within the scope of the invention.

[0042] The embodiments of the invention described above are thus in no way intended to restrict the invention, and the invention can be modified freely within the scope of the invention. Therefore, the apparatus of the inven- tion need not be exactly as shown in the figures, and other solutions are also possible.