FI71416B - FOERFARANDE FOER ATT MED VAERMEPUMP UTVINNA VAERMEENERGI UR SJEVATTEN OCH JAEMFOERBARA VATTENMASSOR - Google Patents

Abstract

Sea water is supplied in a constant or variable flow to a heat exchanger (3) and returned to the sea. A heat carrying medium is pumped simultaneously through the heat exchanger (3) and a supply conduit (7, 11) to an evaporator for a per se known heat pump (8) and through a return conduit (12, 9) again to the heat exchanger (3). The medium is pumped in a flow exceeding the flow through the evaporator, and a part of the medium is directed from the supply conduit (7) past (10) the evaporator and to the return conduit (9). The sea water flow is of a size at least equal to the medium flow.

Description

71416

Method for recovering heat energy from lake water and comparable water masses by a heat pump Förfarande för att med värmepump utvinna värmeenergi ur sjövatten och jämförbara vattenmassor

The invention relates to a method for recovering thermal energy from lake water and corresponding water masses.

Due to the threat of declining available forms of energy today, especially oil-5, both seasonally and in the long run, and the associated high, ever-rising prices of available forms of energy, it has become increasingly fascinating to try to recover lower heat stored in nature, especially for heating purposes. . In addition to the direct utilization of solar heat, attempts are thus being made, especially in the more Nordic latitudes, that heat pump technology uses heat in the air, ground and water for heating purposes, among other things.

Unfortunately, at northern latitudes, warmer air temperatures rarely coincide with heating needs, which is why the method of recovering heat energy from the air has proven to be less economically justifiable in the context of heat pump technology.

Methods have been developed to try to take advantage of geothermal heat that does not fall below + 0 ° C below the depth of frost-20. Heat received in the “summer half” of the year and stored in the ground can be utilized in the “winter half” of the year.In principle, thermal energy is recovered by placing very long hoses or pipelines at a suitable depth and circulating a heat exchanger (eg water or glycol) it in the heat pump evaporator.

A parallel form or alternative to these methods is to recover the thermal energy stored in the sea, lakes and water bodies during the warmer part of the year instead of the winter half of the year. During the colder periods of the year, the temperature of 2 71416 is relatively constant at the depth characteristic of the body of water in question. In practice, the heat energy is also recovered by placing hoses or pipelines at the bottom of the lake inside the heat transfer fluid, which transfers the heat energy received to the heat-5 pump evaporator.

Apart from purely manufacturing and installation difficulties, in addition to large land or floor area requirements, both of the latter methods also present major operational problems.

10

The ground mass around the pipeline, as mentioned, keeps the temperature slightly above + 0 ° C, normally + 1 ... + 2 ° C. By dissipating heat with the heat transfer medium, the temperature of the surrounding ground mass decreases all the time. A temperature below + 0 ° C is reached, which causes ice to form around the line and, as a result, lower efficiency.

A similar fact can be said to apply to the lines placed in the lake. During the “winter half” of the year (with climate- and latitude-dependent time shifts), the lake water maintains a temperature of about + 1 ... + 2 ° C. ice is formed, which means an increase in the insulation of the pipeline and impairs its heat transfer rate and at the same time the efficiency of the device.

25

In addition, the pipelines are exposed to external contamination, e.g. algae plants stratify on them, which also lowers efficiency.

The present invention, as set forth in the claims, enables heat pump technology to continuously recover the thermal energy of lake water or comparable water masses during the colder season of the year, thereby selecting design values so that lake water near freezing point can be utilized. using power without impeding ice formation.

This means that full energy output can continue during the coldest period of the year, 3 January 2014, for example in January, February and March.

The invention will be described in more detail in the form of an example with reference to the drawings, in which Figure 1 shows very schematically one device for carrying out the invention and Figure 2 another device in another form.

The heat exchanger 3 is placed directly in the lake water (Fig. 1). The heat transfer medium, for example a mixture of water and glycol, is pumped by the pump 6 through heat exchangers or lines 3 and 11 to the evaporator of the heat pump 8, which is known per se and not described in more detail here. From here, the heat transfer medium is led back to the heat exchanger 3 via lines 9 and 12. The bypass line 10 connects lines 7 and 9 to each other, bypassing the evaporator. 4 generally shows the lines that connect the heat pump condenser to it or to the heating systems served by the heat pump. 13 15 shows the surface of lake water. The heat exchanger 3, in which the heat transfer medium recovers the heat of the lake water, can best be of the type in which the heat transfer medium flows into concentrically arranged pipe coils between which the lake water flows. The brushes placed on the arms rotating about a common centerline of the coils make it possible to keep the heat exchanger surfaces of the coils free of Taina lake water contaminants as well as to prevent them from overgrowing with Levi and other aquatic plants while forcing lake water to flow along and between the coils. The brushes are effected to rotate by a drive motor, e.g. an electric or hydraulic motor 25, the latter can be used in pump-operated heat carrier system as j.

The heat exchanger has a lake water inlet at the bottom of the exchanger. This opening can be flushed into a wire with a mouth at a suitably deep location to take advantage of the maximum heat content of the water during the tal-30 fault. The principle of such a heat exchanger is described in Swedish Patent 7706927-6 and Swedish Patent Application 7908805-0.

If it is more suitable to place the heat exchanger in a place other than the lake 35 (Fig. 2), the lake water can be pumped through the line 1 by the pump 2 to the heat exchanger 3 and back to the lake via the line 5. The inlet end of line 1 is located in a place in the lake where the highest possible temperature during the first half of the winter prevails.

The outlet end of the line 5 can in principle be located anywhere, but away from the inlet pipe, so that the temperature of the water to be discharged does not affect the water mass around the inlet pipe 5. In the same way as described above, the pump pumps the heat transfer medium from the heat exchanger 3 via lines 7 and 11 to the heat pump evaporator. From here, the heat transfer medium is again led through lines 9 and 12 to heat exchanger 3. The bypass line 10 connects lines 7 and 9 to each other, bypassing the evaporator. 4 10 generally shows the lines that connect the heat pump condenser to it or to the heating systems served by the heat pump.

13 shows the surface of lake water and 14 shows the surface of lake water inside the heat exchanger.

15 One way of locating a heat exchanger in which lake water flows through a pump can be illustrated by the following example.

During the cold season of the year, lake water with a temperature of, for example, + 2 ° C is pumped via line 1. The lake water, which is pumped relatively abundantly, transfers heat in the heat exchanger 3 to the heat transfer medium and leaves the exchanger via line 5 at a temperature of +1.5 ° C. The heat transfer medium, which has a slightly lower flow, reaches the heat exchanger 3 at a temperature of - 1 ° C, absorbs heat from the lake water in the heat exchanger and then exits the heat exchanger by example a degree warmer, i.e.

At 25 + 0 ° C. The heat transfer medium has this temperature when it reaches the evaporator surfaces of the heat pump 8 via line 11. Heat is released in the evaporator (assumed evaporation temperature - 7 ° C and the heat transfer medium exits the evaporator via line 12 at - 4 ° C. The flow through the evaporator is about 1/4 of the heat transfer medium flow through the heat exchanger and this part - 4 ° C). the heat transfer medium mixes with the remaining 0 ° C part of the heat transfer medium after the bypass line 10 in the line 9, whereby the temperature of the heat transfer medium when it reaches the heat exchanger 3 is previously mentioned - 1 ° C. which also has a high flow and which is partly passed past the evaporator of the heat pump, it is possible to reach close to the freezing point without ice forming on the surfaces of the heat exchanger 5 Bypass valve is preferably provided in the bypass line 10 to control heat input to the evaporator, preferably as a constant or by varying it according to the load requirement, within certain limits depending on the varying temperatures of the lake water and at the same time the heat-5 transfer medium.

In the event that the lines 11 and 12 are long, for example for technical reasons, the flow resistance in these lines becomes far too high for the controlled bypass flow in 10 to be made possible only by means of the bypass valve. In order to obtain a precisely controllable bypass flow in such a case, a pump is provided in the line 11, e.g., indicated by reference numeral 15 in Fig. 2, by means of which the flow rate through the lines 11,12 is regulated.

Within the scope of the invention, it is even possible to allow controlled, limited ice formation in the heat exchanger 3 depending on the external conditions, the water temperature and the types of heat transfer media. The invention is also not limited to the shown location of the heat exchanger, but this can of course also be arranged below the water surface.

Claims (3)

6 7141 6 A method for applying thermal energy from lake water and comparable water masses, characterized in that the lake water is led in a constant or variable flow with respect to heat ratios from a suitably selected water mass location to the heat exchanger (3) and again 5 back to the lake to pump the heat transfer medium , 11) through a heat pump (8) known per se to the evaporator and via a return line (12,9) back to the heat exchanger (3), whereby the medium is pumped in a flow greater than the flow of the medium through the evaporator and part of the medium is led to the inlet line (7) past (10) to the evaporator and return line (9), and that the flow of lake water is at least equal to the flow of medium. Method according to Claim 1, characterized in that part of the medium is controllably led from the inlet line (7) past the evaporator to the return line (9) by means of a bypass valve. Method according to Claim 1, characterized in that part of the medium is controllably led from the inlet line (7) past the evaporator to the return line (9) by means of a pump in the line between the evaporator and the medium evaporator bypass line.