SE528862C2 - A heat exchange device - Google Patents

Abstract

The present invention relates to a coil support device for supporting a tubular coil in a water container, wherein said coil support device consists of a coil support element and an elongated coil support locking element, wherein said coil support element consists of an elongated structure having a plurality of substantially transversal cut-outs, each adapted for receiving a portion of a respective turn of said tubular coil. The said coil support device is arranged to be applied to said coil such that an elongated space is formed between said coil and said coil support element, and said elongated coil support locking device is arranged to, from one end of the coil support element, be inserted into said space formed between the coil and the coil support element so as to, in use, lock said coil support element to the coil. The present invention also relates to a heat exchange arrangement.

Description

temperature available is limited by the temperature at which the heat pump is able to heat the primary water, there is a limitation on the temperature to which the secondary water can be heated.

The currently commonly used method for hot water production is that a double-jacketed water tank is used, where the consumption water is in the inner container and is heated through the container wall by hot water in the double-jacket space.

A problem with this type of water heating is that heat pumps with high output power, e.g. over 6 kW, when heating the hot water tends to, especially during summer operation, switch on and off several times during heating, charging, of the hot water, which leads to a poor utilization rate of the heat pump.

OBJECTS AND MOST IMPORTANT FEATURES OF THE INVENTION The object of the present invention is to provide a system which solves the above problems.

This object is achieved by a system as defined in claim 1.

The system comprises a heat exchanger device which includes a water tank with an inlet for supplying water to be heated and an outlet for discharging heated water.

The heat exchanger device further comprises a pipe loop arranged inside said water tank, said pipe loop extending through substantially the entire water-bearing height of the water tank, said pipe loop further comprising at its upper end an inlet for receiving hot water, and an outlet for discharging said hot water after passage. , the loop being made of a material which allows heat from the hot water to be given off to water in the tank at the hot water 73l50d.doc; 11/10/06 passage through the loop. The outlet of the pipe loop can be arranged in the lower end of the pipe loop.

This has the advantage that by directing the hot water through the pipe loop instead of a double jacket, a heat-dissipating surface that is significantly larger than the jacket surface can be obtained, which increases the heat exchanger's heat transfer capacity and thus enables more heat to be delivered to the water in the tank.

Furthermore, the solution with the pipe loop has the advantage that a significantly higher speed of the hot water can be obtained compared to what is possible with the double jacket solution, which further increases the heat transfer. In addition, the solution according to the present invention enables the heat transfer surface to be placed more freely than with the double jacket method, which has the advantage that a larger temperature gradient can be obtained in the tank.

The pitch of the pipe loop can be evenly distributed over its length or vary over its length. For example. the rise may be lower at the top and bottom compared to the middle. This has the advantage that the heat-dissipating surface can be adapted to obtain the best possible temperature stratification in the tank.

The hot water can be circulated through the pipe loop by means of a circulation pump. The circulation pump can further be controlled continuously or against predefined start and stop conditions. For example. the circulation pump can be controlled in such a way that the circulation pump is switched on at a first refrigerant condensing pressure and switched off at a second refrigerant condensing pressure which is lower than the first refrigerant condensing pressure. Alternatively, the circulation pump can be controlled in such a way that the refrigerant condensing pressure is kept at a predetermined value. This has the advantage that the ability of the heat exchanger device to heat water can be varied based on different needs, For example 73l50d.döc; 11/10/06 LH í J 'h _ \ .p ^ \ d C 3 <ÃÉW FO, an uncontrolled circulation pump can mean that a slightly smaller volume of ready-mixed hot water can be taken out of a fully heated water tank, but where the hot water production has taken place at a lower cost when the efficiency of the heat pump has been high, while controlling the circulation pump towards a certain operating point can enable a higher temperature in the water tank, which in turn means that a large consumer can get a larger amount of ready-mixed hot water (ready-mixed hot water consists of the total volume of hot water in the tank and the volume of the cold water with which the hot water is mixed) but at a higher cost due to lower efficiency.

The heat exchanger device may further comprise a double jacket whose space can be used as an accumulator tank for e.g. defrost water. This has the advantage that if the heat pump uses outdoor air as a heat source, the space in the double jacket can be used as a defrost tank for defrosting an air heat exchanger if necessary or at regular intervals.

Heat exchanger device may further be provided with loop support to hold the pipe loop in place. This has the advantage that the pipe loop can be mounted in the tank in the factory and then transported to an installation site without risking the loop sagging and being damaged, which could otherwise be the case if the pipe loop e.g. is made of copper. A further advantage is that the pipe loop can easily be positioned in an optimal way in the tank both in terms of placement relative to the tank wall and the location of the individual loop turns.

Brief description of the drawings Figures 1a and 1b generally show a heat pump.

Figure 2 shows a preferred embodiment of the present invention. 73l50d.doC; 11/10/06 LH Get C: CG 3. 3 Figures 3a and 3b show a solution for holding the pipe loop in place.

Detailed Description of Preferred Embodiments Fig. 1 shows a heat pump 10 installed in a property such as a villa. The heat pump 10 is provided with a control computer 12, which controls and monitors various functions in the heat pump. Examples of such functions can be setting and / or monitoring working temperatures for the heat pump's compressor, indoor and outdoor temperatures, setting the heating curve, controlling the room temperature depending on the time of day or holiday, etc. A user can communicate with the control computer 12 via the heat pump 10 arranged display 28 and keypad 29. The heat pump 10 further comprises a heat pump circuit 20 and a water tank 11 with an inlet 13 in the lower part of the tank for supply of water to be heated and an outlet 14 in the upper part of the tank for discharge of heated water.

The heat pump circuit 20 comprises circulating refrigerant where liquid refrigerant 20 absorbs heat from heat source such as a rock heat loop 22 with a temperature of approx. -5 ° - + 5 ° and evaporates in an evaporator. The evaporation temperature can e.g. be -3 °. The gaseous refrigerant is then compressed by means of a compressor 23 to a higher pressure, which due to the smaller volume of the gas causes the gas temperature to rise. The compressed, hot gas then gives off its heat via a condenser 24 and a subcooler 25 its heat to the so-called the primary water, the radiator water 26. The subcooler means that additional heat can be extracted and thus provides a more economical heat pump. Via an expansion valve 27, the pressure of the now liquid refrigerant is then greatly reduced, whereby the temperature of the refrigerant drops rapidly, after which the refrigerant again absorbs heat from the rock heating coil 22. 73l50d.doC; 11/10/06 The heating coil can also absorb its heat from soil, air and / or water.

The primary water is then used alternately to heat domestic hot water or the property's radiator and / or floor heating system. The efficiency of the heat pump is controlled by the temperature of the refrigerant when it reaches the condenser, the lower the temperature, ie. the lower the pressure, the higher the efficiency.

When heating the primary water to e.g. 35 ° with a 10kW heat pump, the heat pump's so-called coefficient of performance (COP), ie. the ratio between output power and applied power, be 4.4, at 50 ° it can be 3.3 and at 60 ° it can be 2.7.

Thus, the heat pump can not heat the primary water to any high temperature, at least not in an economical way, which leads to limitations on how much the secondary water, the domestic hot water, can be heated by the primary water.

Fig. 1 shows the currently commonly used method of heating the secondary water. The water tank 11 is double jacketed with an outer jacket 15 surrounding the tank 11. The primary water is circulated alternately via a changeover valve through the housing heating system (not shown) and through the space 16 between the tank 11 and the jacket 15. When the hot primary water passes through the space 16 the water in the tank is heated 11 via the tank surface 17. When the primary water reaches the bottom of the double jacket, it is led via an outlet 18 back to the heat pump part 20 to be heated again.

A problem with this solution, however, is that the primary water when it is returned to the heat pump part 20 due to poor heat dissipation via the mantle surface can still have such a high temperature that the heat pump in turn switches off due to that the refrigerant cannot emit its heat. This in turn results in 73150d.doc; 11/10/06 LH FS m ". \ Piø CG CJK cause the water in the tank to not heat up fast enough in some cases, which in turn can result in the hot water, especially for large consumers such as a family with many children, running out even though it In fact, there is a capacity for additional heating, and the fact that the heat pump switches off frequently also means that the effective running time is low and that its capacity is thus not utilized to the extent that could be possible.

Figure 2 shows a heat exchanger device according to the invention which enables a greater heat dissipation to the water in the tank and also a larger hot water outlet. Instead of a double jacket, a pipe loop 31 is instead arranged in the water tank 30 which extends through substantially the entire part of the water tank 30 which is filled with water. The primary water heated by the heat pump part is let into the pipe loop from above and circulates through the loop which ends with a passage through the bottom of the tank, after which the primary water is recirculated to the heat pump part for new heating before it is circulated again through the loop. The pipe loop has the advantage that, compared with the jacket surface, a significantly larger heat dissipation surface is obtained, which means that a larger amount of energy can be emitted when passing through the loop. This further means that the temperature of the primary water after passage through the loop will be lower compared to the solution in Fig. 1, which in turn means that a larger amount of energy can be taken up from the heat pump's refrigerant, whereby the heat pump does not have to switch off as often. Thus, the water in the water tank can be preheated (fully charged) faster and thus in a shorter time than before again allow hot water withdrawal after a previously large consumption of hot water. The figure shows the loop with an essentially square cross-section in the axial direction, however, this cross-section can of course also be circular, triangular or of some other polygonal shape. As can be seen in 73l50d.doc; ll / 10/06 01 IJ f: f 'Rv IW á \ .r »J GW FJ the figure is in this case the pipe loop and the water tank coaxially arranged.

Because the loop extends through all or substantially the entire water-containing part of the tank, a larger temperature gradient is also obtained than that obtained with the double jacket solution, ie. even if the total energy content of the water tank is the same, the temperature difference between top and bottom will be larger with the pipe loop, which results in the temperature in the upper part being higher with the pipe loop compared to using the double jacket. In heat pump applications, each additional degree of temperature for the domestic hot water is important as this results in a larger amount of ready-mixed water with a consumption-friendly temperature being obtained. The present invention thus makes it easier to achieve the common norms for how much hot water a water heater should be able to deliver in a continuous bottling and then again in a new bottling after a certain time, e.g. one hour.

In an example of a heat pump according to the invention, a peak temperature is obtained which is about 5 ° higher than when using a double jacket solution. In addition, recharging is much faster because the heat pump does not switch off in the same way as when using the double jacket solution.

Compared with the double jacket solution, the present invention also has the advantage that the weight of the overall device becomes lower and the heat pump thus becomes easier to transport and to install.

In an alternative embodiment, the double jacket can be retained. If the heat pump e.g. using outdoor air as a heat source, a defrost tank with hot water is normally needed, which is circulated to an air heat exchanger with a flange package to thaw ice 73l50d.dOC; 11/10/06 ß fi 53 GQ Cïn TJ which folds out on the flange package. This defrost tank normally constitutes a separate unit located next to the heat pump.

However, the present invention enables the free space in the double jacket to be used instead as a defrost tank. Water that has cooled down when heating the flange package can then be reheated by the domestic hot water through the jacket surface of the water tank and then shunted out to the flange package if necessary. The limited ability of the jacket surface to transfer heat to the defrost water results in the temperature of the domestic hot water being affected only to a small extent. The invention thus has the advantage that the extra tank does not need to be used, with both cost and space savings as a result.

The water is circulated through the pipe loop by means of a circulation pump. Normally there is no control of the circulation pump, but this circulates the water continuously. To further improve the heat pump's ability to deliver larger amounts of domestic hot water, a control of the circulation pump can take place. For example, a simple control principle can be applied, where the circulation pump starts when the condensing pressure in the heat pump has reached e.g. 25.5 bar, which means that the refrigerant has a high temperature and that the primary water will thus be heated to a high temperature when the circulation starts. When the condensing pressure after starting the circulation pump has then dropped to e.g. 20 bar p.g.a. heat dissipation to the primary water, the circulation pump is switched off until the condensing pressure has risen again to 25.5 bar. This control method is thus very simple and can be implemented in a simple way. The advantage of this control method is that even more hot water can be taken out of the boiler, especially when withdrawing hot water at higher temperatures such as 50 ° hot domestic hot water. This control method also results in an even larger temperature difference in the tank and thus a higher peak temperature.

The disadvantage of the control is that the COP of the heat pump is lower than 73l50d.doc; 11/10/06 LT! WS CE nn. hia-f F., vw; s n ~ I 10 in case of uncontrolled circulation pump due to the higher condensation temperature.

To further increase the possibility of extracting large amounts of domestic hot water, a continuous control of the circulation pump can be applied. With continuous control, the operating point of the heat pump compressor can be kept around a predetermined point, e.g. 26 bar, which enables an even larger volume of hot water with a high temperature to be extracted, which can be advantageous for large families or on occasions with overnight guests. However, the lower COP factor means that the heating cost is higher.

The above pressures for starting and stopping the circulation pump are only an example and should be chosen to be lower than the condensing pressure at which the heat pump switches off.

The water heater can also be equipped with a sensor at the top of the water heater to enable the display of the actual hot water temperature. This sensor can also be used to control hot water production_ For example, the heat pump can be switched off when the peak temperature has reached a certain temperature. This has the advantage that a customer e.g. can choose the temperature at which the heat pump should switch off. If the household is not a large consumer of hot water, perhaps 45 ° or 50 ° in the top of the tank is sufficient for a sufficient amount of ready-mixed water for the household to be obtained from the hot water in the water tank. The sensor can also be used to start the heat pump when the peak temperature is below a certain value, e.g. when the temperature has dropped due to hot water outlet or heat dissipation via radiation, e.g. when the tank has been unused for a period.

Fig. 3a shows a solution for holding the pipe loop in place.

In order to e.g. avoid the loop collapsing during transport 73l50d.do <: 7 ll / lO / OG 523 852 ll p.g.a. shaking, blows, etc., which can happen if the loop e.g. is made of copper, a loop support device can be used to hold the loop in place. The figure shows two diametrically opposed loop support devices 41, 42 which are used to support a loop 40 in a tank 43.

The loop support devices 41, 42 each consist of two separate parts, one 44 constituting the loop support itself and the other 45 constituting a loop support lock.

In Fig. 3b the parts 44 and 45 are shown in more detail. The loop supports are preferably made of a thermoplastic such as polyethylene or polyoxymethylene and consist as an example of a 2 mm thick plate with groove 46 for the pipe loop. When mounting, bend the loop support at about 90 degrees with the help of a tool and thread it over the corner of the loop. In the space formed between the loop and the loop support, a loop support lock in the form of a rigid wire is threaded in from one end. Fig. 3a shows the loop support both in the bent state and in the flat state.

The loop support lock consists of e.g. of a round bar of polyethylene or polyoxymethylene. For a heat exchanger for a villa heat pump of normal size, the lock can have a diameter of about 8 mm and be about 900 mm long.

Two loop supports are mounted in this way on each loop in two opposite corners of the loop. To reduce the number of parts, the two loop supports can be identical but be designed so that compensation for the slope of the loop takes place by turning one support upside down. When transporting the heat exchanger, the lower ends of the loop support support the lower part of the tank, thus keeping the loop in place and preventing it from collapsing during transport. The loop support also ensures that the correct positioning of the loop in the water tank is maintained during the life of the heat exchanger. In an alternative embodiment, the loop support may be completely flat but designed as 73l50d.doc; 11/10/06 12 that it can still be threaded over a corner of the loop, e.g. the corners of the loop in this case can be relatively sharp. 73l50d.dOC: 11/10/06

Claims (4)

Un NJ ha * v CS (f. A. * S I KJ 13 PATENTKRAV 1. A system comprising a heat exchanger device for use with a heat pump, an oil boiler, a wood boiler or the like, the heat exchanger device including - a water tank (30) having an inlet for supplying water to be heated and an outlet for discharging heated water. water, the heat exchanger device further comprising: - a pipe loop (31) arranged inside said water tank (30), said pipe loop (31) further comprising an inlet for receiving hot water, and an outlet for discharging said hot water after passage through the loop, wherein the loop is made of a material which allows heat from the hot water to be given off to water in the tank (30) Upon hot water passage through the loop, the system further comprising means for heating the hot water by means of a heat pump, the hot water being circulated through the pipe loop (31 ) by means of a circulation pump, the system comprising means for controlling the circulation pump continuously or against predefined start and stop conditions, characterized in that the system comprises means for - controlling the circulation pump in such a way that the circulation pump is switched on at a first refrigerant condensing pressure and switched off at a second refrigerant condensing pressure which is lower than the first refrigerant condensing pressure. System according to claim 1, characterized in that instead of comprising means for switching on the circulation pump at a first refrigerant condensing pressure and switching it off at a second refrigerant condensing pressure, it comprises means for controlling the circulation pump in such a way that the refrigerant condensing pressure is kept at a predetermined pressure . 73l50d.doC; ll / 10/06 14 System according to claim 1, characterized in that instead of comprising means for switching on the circulation pump at a first refrigerant condensing pressure and switching it off at a second refrigerant condensing pressure, it comprises means for controlling the circulation pump based on the peak temperature of the tank (30). System according to any one of claims 1-3, characterized in that said pipe loop (31) extends through substantially the entire water-bearing height of the water tank (30), said inlet for receiving hot water being arranged at the upper end of the loop. 73150d.doc: 11/10/06