SE529437C2 - System for utilizing cold from snow for cooling buildings or for cooling purposes in processes, has openings with filtering elements on sides of each well and at even heights of upper portion of well, and flanged lid provided for well - Google Patents

Abstract

The system has a basin-like snow store (3), a piping system (23) for circulating melt water, a pump (9), and a heat exchanger (10). The snow store has at least two wells (2), each including openings (16) with filtering elements on sides and at equal heights on the upper portion. A flanged lid is provided for each well.

Description

lO 529 437 2 JP20023lO583 shows a facility for snow cooling where the snow layer is above ground. A problem with the plant in JP20023l0583 is that the snow layer must be built up in height, for example with the help of front loaders. Another problem is that the snow layer must be insulated around when the snow layer is closed again for the season.

There are known snow layers for snow cooling which are pool-like. An advantage of pool-like snow layers is that snow can be tipped down to a snow layer from trucks, alternatively snow can be distributed down to the snow layer with the help of a front loader. Another advantage is that a pool-like snow layer only has a direction that needs to be insulated when the snow layer closes before the summer, namely the upper side. The upper side can be insulated, for example, with the help of shavings or bark.

Known pool-like snow layers have an outlet for a first pipe system at the bottom of the snow layer. The bottom of such a basin-like layer of snow typically slopes towards the outlet. The outlet is typically connected to at least one pipe in which melt water is transported by means of a pump through a heat exchanger. The pump thus regulates the flow of melt water through a first pipe system in a snow cooling system. At the outlet there is a filter or grille which intends to separate coarser particles such as bark which is used as insulation of the upper side of the snow layer.

Before the heat exchanger there is an oil separator and a particle separation filter which is intended to filter out particles over a certain size. This is to protect the heat exchanger from clogging. One problem is that if the melt water flowing along the bottom of the basin-like snow layer contains larger amounts of coarser particles, the filter will be clogged relatively often. The problem can be counteracted by using a backwash filter. In the heat exchanger, an energy transfer takes place from the brine, usually water, in another pipe system to the melt water. The temperature of the water in the second pipe system is lowered in the heat exchanger. The water in the second pipe system is distributed to, for example, a building where there is a need for comfort cooling. The second piping system may be a district cooling network. The melt water that has passed through the heat exchanger is returned to the snow layer, for example by letting in water at the sides of the snow layer through a number of nozzles positioned. Alternatively, the recirculating melt water can be sprayed over the snow layer.

After a period of snowmelt, there is typically an excess of meltwater which is then drained from the snow cooling system.

As the bottom of the pool-like snow layer typically slopes towards the outlet, which is located at the bottom, the melt water transports relatively large particles to the first pipe system. A problem with known pool-like snow layers where an outlet is located at the bottom is that not only smaller particles in sediment and other objects must be filtered in at least one felt step after the outlet, but also larger particles must be filtered.

In an ideal snow layer, melt water flows relatively slowly through porous snow and thus a good residence time and contact with the snow is achieved. A problem with known pool-like snow layers is that melt water forms channels to the outlet, which leads to a shorter residence time and a poorer contact with the snow than in the ideal case. 529 437 JP2002235975 shows a snow cooling tank with an outlet at the bottom of the tank for a first pipe system.

The tank includes a number of thresholds. The thresholds lead to improved residence time and improved contact for melt water with the snow layer. A remaining problem is that a number of larger particles are transported in through the outlet. Furthermore, the flow of melt water through the snow layer is not controllable, which means that channel formation cannot be counteracted. OBJECTS AND SUMMARY OF THE INVENTION An object of the invention is to provide a system for snow cooling which reduces the number of particles in melt water which need to be filtered out in filters placed after outlet to a first pipe system from a pool-like snow layer. A further object of the invention is that the indicated system provides an improved contact between the melt water and the snow layer. An advantage of improved contact between the melt water and the snow layer is that the melt water passing through a heat exchanger has a lower temperature than the melt water from previously known pool-like snow layers, which improves the efficiency of energy transfer at the heat exchanger.

This object is achieved by a system according to claim 1. Such a system comprises at least two wells. Each well comprises a number of openings with filtering elements on the sides of the well placed at equal heights on the upper part of the well. Each well includes a collared lid. A collar lid has an edge that extends beyond the side or sides of the well. In 529,437 previously known pool-like snow layers, the bottom of the snow layer is typically sloping towards an outlet at the bottom of the snow layer where a larger amount of sediment and particles are drawn in through the outlet. The wells in the system according to the invention comprise openings above the bottom of the snow layer, which significantly reduces the amount of sediment and particles drawn from the bottom towards the openings compared to the amount of sediment drawn in through the outlets in previously known snow layers. This achieves a better primary filter effect.

The collared lid on each of the wells helps to reduce the amount of particles and sediment that follows melt water into pipes connected to the wells and further out of the pool-like snow layer, this as the collared lid forces melt water from the upper part of the snow layer on its way in. towards the openings to flow at least partially horizontally. Gravity thus contributes to sediment and larger particles being transported to the bottom of the basin-like snow layer.

As previously mentioned, canal formation of meltwater is a problem in previously known pool-like snow layers. A disadvantage of channel formation is that the residence time of the circulating melt water is shortened, and that the contact of the melt water with the snow deteriorates compared with an ideal case where melt water seeps through the pores of the snow in the lower water-filled part of the snow layer. In the system, the raised wells have a number of openings for melt water in the upper part of each well which results in a smoother flow of melt water through the snow layer which improves the contact with the snow. A relatively extensive part of snow melting takes place at the sides of the snow layer, which means that the melt water flow is relatively extensive at the sides and further along the bottom of the snow layer. An advantage of the system is that the flow of melt water is forced upwards from the bottom towards the openings in the wells. Since the wells comprise a number of openings, a given volume of melt water passes a larger volume of snow compared to previously known pool-like snow layers with openings at the bottom, which counteracts channel formation and thus improves the contact with surrounding snow.

A pipe is connected to each well, which forms part of the circuit for circulating melt water. To further counteract the undesirable effects of duct formation, a valve is provided for each of these pipes. When a valve is throttled or closed, the flow of melt water in the channels that may have arisen to the corresponding well decreases or ceases. The channels disappear as the surrounding snow melts away, as the valve eats opens. The flow of meltwater towards the wells' openings then passes through a larger volume of snow. This improves the contact between the melt water and the snow. During the time when the valve is throttled or closed, the flow to the other wells will increase, provided that a constant volume of melt water is pumped through the pipe system.

In addition, the water that previously sought its way to a certain well will be forced to seek new paths.

A snow cooling system according to the invention may be intended for cooling a number of objects within a geographically delimited area, via a district cooling network.

Alternatively, the system may be intended for cooling an individual facility, such as a hospital or an office property. Furthermore, the snow cooling system 529 457 7 can be used for process cooling in industrial processes or to reduce electricity consumption in a cold store.

DESCRIPTION OF FIGURES The invention is explained in more detail with reference to the accompanying figures, where Figure 1 shows a schematic overview of a system 1 according to the invention. The system comprises at least two raised wells 2. Most of the flow of melt water takes place through the snow and along the bottom of the snow layer 3. The system according to the invention counteracts channel formation, partly because the openings are raised from the bottom and also because the openings are more than in traditional snow layers with outlets. at the bottom of the snow layer. The figure shows that in a system according to the invention, melt water is forced at the bottom 13 upwards towards the inflows into the raised wells 2, which gives an improved residence time and better contact between the melt water and the snow. An improved residence time leads to the temperature of circulating melt water being lower than in previously known systems.

Figure 2 depicts a basin-like snow layer 3. A raised well 2 with openings in its upper part means that sediment 14 which falls to the bottom is not drawn into the openings. Figure 2 further shows that the collared lid 17 forces inflowing water to be moved at least partially horizontally, which means that sediment from the upper part of the snow 6 tends to fall to the bottom. A certain amount of sediment 14 settles on the lid. in 529 437 8 Figure 3 is a side view of a raised well 2. The well in Figure 3 has a height with a dimension greater than the diameter of the well.

Figure 4 shows an example of a basin-like snow layer 13 which comprises three raised wells 2a, Zb, 2c. The main flow paths for melt water 5 'are indicated in Figure 4.

Figure 5 shows the same example of a basin-like 2b, 2c a pipe l5a, l5b, l5c is connected. In figure 5, the valve has snow layers as in figure 4. To each well 2a, 22c has been closed, which means that the inflow of melt water to the well 2c has stopped. The channels that melt water forms towards the well 20 melt away when the melt water which had previously sought the well 2c instead seeks the two other wells 2a, 2b.

DESCRIPTION OF EMBODIMENTS The system in Figure 1 comprises at least two raised wells 2. The majority of the flow of melt water typically takes place through the snow and along the bottom of the snow layer 3.

The figure indicates that below a level 21 in the snow layer is most of the melt water. Return pipes 19 for melt water can be connected to discharges in the sides of the pool-like snow layer 3. Return lines 19 for recirculating melt water can alternatively be connected to nozzles which, like water sprinklers for lawns, spread the recycled melt water over the snow 6. The system according to the invention the openings are raised from the bottom and also because the openings are more than in traditional snow layers with openings at the bottom of the 529 437 9 snow layer, which means that you can vary the flow paths.

The figure shows that in a system according to the invention, melt water is forced at the bottom 13 upwards towards the inflows into the raised wells 2, which gives an improved residence time and better contact between the melt water and the snow. The figure further shows that the system comprises components such as a gravel and oil separator 7, a filter 8, a pump 9 and a heat exchanger 10. It can be considered obvious that the system can comprise a plurality of these components. Figure 1 shows that a second pipe system leads cooled water from the heat exchanger 10 to a cooling object 11 which can be, for example, a number of buildings. The pump 9 regulates the total flow of melt water through the pipe system 23 and thus also the flow through the openings 16 in the wells. Excess melt water can be discharged from the system through a discharge 20. The height of the wells is typically at least 0.5 meters, so that sediment that has fallen to the bottom is not sucked into the openings 16.

Figure 2 depicts a basin-like snow layer 3. A raised well 2 with openings 16 in its upper part means that sediment 14 which has fallen to the bottom is not drawn into the openings 16. Figure 2 further shows that the collared lid 17 forces inflowing water to be at least partially moved horizontally which means that sediment from the upper part of the snow 6 tends to fall to the bottom 13, instead of being drawn in through the openings 16. In figure 2 an outgoing pipe 15 is arranged below the bottom 13 of the snow layer.

Figure 3 is a side view of a raised well 2. The well 2 comprises a number of openings 16 with filtering elements on the sides 2 'of the well 2. The openings 16 are located on the upper part of the well 2. The filtering elements may be net-like. The well 2 can be arranged at the bottom 13 in a number of ways. The well in figure 3 comprises a bottom plate 18 which is arranged on the bottom 13 of the basin-like snow layer 3. The bottom plate 18 can, for example, be screwed into a cast foundation. Another alternative is that the well 2 is cast to the bottom 13, which can be a special advantage if the bottom of the pool-like snow layer is paved. The well 2 comprises a collared lid 17 which projects over the sides 2 'of the well 2. The main body of the well 2 is advantageously cylindrically shaped. The main body can then be manufactured from pipes that are cut. At one end of the cut pipe, sockets for the openings 16 can be created, for example by milling. Well 2 can, for example, be made of polyethylene, fiberglass or stainless steel. The lid 17 can, for example, be glued, heated or welded to the main body of the well 2. The pipe 15 from the well 2 can be arranged above the bottom 13. In that case, breaking forces against the pipe 15 can advantageously be counteracted by the pipe resting against a sand bed.

The pipe 15 can alternatively be arranged under the bottom 13, which facilitates cleaning of the bottom 13 after the summer when the system is taken out of operation.

Figure 4 shows an example of a basin-like snow layer 13 which comprises three raised wells 2a, 2b, 2c. To each well 2a, 2b, 2c there is a pipe 15a, 15b, 15c connected. The pipes are advantageously connected in a position before the oil separator. The main flow paths for melt water 5 'are indicated in Figure 4.

The system according to the invention counteracts the formation of channels, which gives the previously mentioned beneficial effects of longer residence time as well as improved contact 529 437 II with the snow. Figure 4 shows that compared with previously known snow layers where the bottom slopes towards an outlet at the bottom, the melt water seeks via a larger number of paths, and longer paths towards the openings 16. At least two wells 2 are necessary for the beneficial effects to be achieved.

Despite the beneficial effects, a limited number of channels will arise at the bottom l3 of the snow layer 3.

Figure 5 shows the same example of a pool-like snow layer as Figure 4. At each pipe 15a, 15b, 15c a valve 22a, 22b, 220 is arranged. In Figure 5, the valve 22c has been closed, which means that the inflow of melt water to the well 2c has stopped. The channels that melt water forms towards the 5 'well 2c disappear when the snow around it melts away. Melting water 5 "from the area around well 2c instead seeks further towards the other two wells 2a, 2b.

The invention is not limited to the above-mentioned embodiments, but can be varied in many ways within the scope of the appended claims.

Claims (1)

A snow cooling system comprising a pool-like snow layer (3), a tubular system (23) for circulating melt water, a pump (10), further comprising at least two wells (9) and a heat exchanger characterized in that the system (2), that each well (2) comprises a number of openings (16) with filtering elements on the sides (2 ') of the well (2) placed at equal levels to each other on the upper part of the well (2), that each well (2) comprises a collared lid (17). A system according to claim 1, characterized in that a pipe (15a, 15b, 15c) is arranged on the lower part of each well (2), which pipe (15a, 15b, 15c) forms part of the pipe system (23) for circulating melt water, that to each of these pipes (15a, 15b, 15c) there is a shut-off device (22a, 22b, 22c) arranged to regulate the flow of melt water through the well (22) to which the pipe is connected, whereby the flow of melt water through formed channels (5 ') to the well decreases. A system according to patent claim 1 or 2 where the height of the wells is at least 0.5 meters.