in particular an evaporator for manufacturing and storing

ice

The object of the invention is a heat exchange unit for the devices with a heat pump, used in particular as an evaporator in the device for manufacturing and storing ice.

Heat exchange between liquid streams of different temperatures is the basis for the operation of many industrial devices and those used privately in everyday life. The most common are heat exchangers with a partition through which heat exchange occurs with a cross flow of liquids. In addition to, for example, car radiators, boiler furnaces and solar collectors, exchangers are used in refrigeration and air conditioning, in devices with heat pumps, realizing the Linde thermodynamic cycle.

Among many known heat exchangers, solutions with a constructional system called "harp" are often used. For example, such exchangers are described in patent specifications WO 2013055519, US 20120292004 and US 20150122470. The exchangers comprise the inlet collector and the outlet collector, included in the circulation of the thermodynamic medium, which in a parallel and spaced apart position are connected through the perpendicular tubular flow channels. In the exchanger of WO 2013055519 the flow channels are connected to the plate of the radiator, which may be a web sheet having a plurality of grooves tightly adhering to the pipes of the flow channels or after joining together two of such sheets they form a surface unit ensuring good thermal conductivity.

The efficiency of the heat exchanger is primarily dependent on the heat exchange surface and the homogeneous temperature conditions on this surface. In the exchanger of US 2012092004 - in order to ensure the most even flow through all flow channels connected perpendicularly to the inlet collector and the simultaneous occurrence of similar phase transitions therein and in specific places - a tubular nozzle distributor was used, an example of which is described based on Fig. 6. The distributor is inserted longitudinally into the collector and has nozzle orifices directed coaxially to the flow channels along the side. There is a gap between the nozzle orifices and the orifices of the flow channels in the wall of the inlet collector, in which the swirls of the streams are suppressed - which is important especially for the nozzles in the initial section. The nozzle orifices in the wall of the tubular nozzle distributor have diameters increasing successively from the end with the thermodynamic medium supply. The description includes flow rate charts in individual flow channels for an exemplary embodiment of the exchanger. The specification US 20150122470 shows a concept of a tubular nozzle distributor, consisting in shortening the distributor pipe to 1/3 to 3/4 length of the inlet collector and with the blinded end enlarging the last nozzle orifice at the same time. According to the applicant, the prototype made according to the invention showed virtually uniform flow rates in individual flow channels with a preferred reduction in the pressure drop across the outlet collector - which, according to the inventor, resulted in the increase of exchanger efficiency by approximately 15% compared to a conventional solution.

Patent specification JPH 08261518 discloses also an exchanger of the device for manufacturing ice. The radiators of the exchanger arranged horizontally and at intervals above each other are included as evaporators in the thermodynamic circuit of the heat pump. The orifices which help to detach the ice with the flow of heated water after switching the exchanger cycle with the evaporator function on the condenser in the de-icing phase are present in the plates of the radiator, on both sides along the meandering flow channels holes.

In harp exchangers, in particular of high efficiency, the phase transition of the thermodynamic medium starts at the inlet collector, passes through the flow channels and ends at the outlet collector- resulting in the temperature differential on the heat exchange surface. For many devices with a heat pump, uniformity of temperature on the entire exchange surface is very important for their efficiency. For example, in addition to refrigerators, this value is important in ice and chilled water devices for air conditioning.

The heat exchange unit according to the present invention, as in the above- described known solutions, comprises a tubular heat exchanger connected by an inlet collector and an outlet collector into the thermodynamic medium circuit of the heat pump. The collectors located in parallel and at the distance are connected by tubular flow channels perpendicular thereto and are connected together by the plate of the radiator while maintaining the heat conductivity. The tubular nozzle distributor, having many nozzle orifices on the side, directed co- axially to the flow channels, is introduced inwards, along the inlet collector. The nozzle orifices in the tubular nozzle distributors have diameters increasing successively from the end of the thermodynamic medium supply. The essence of the invention lies in the fact that the heat exchange unit consists of two identical heat exchangers incorporated simultaneously in the heat pump circuit. Final sections of the flow channel connections to the outlet collectors are bent off the radiator plane, which is determined by long, straight sections of the flow channels coming out from the inlet collector. The deflection has a dimension greater than half the sum of the outside diameters of the inlet and outlet collectors. The heat exchangers are superimposed so that the straight long sections of their flow channels are alternating with each other in the plane of the radiator and are connected with one, common plate of the radiator. On one side of the unit there is: an inlet collector of the first exchanger and the outlet collector of the second exchanger parallel to each other and on the other side an inlet collector of the second exchanger and an outlet collector of the first exchanger. The nozzle distributors of the first and second heat exchangers are built into the adjacent ends of both inlet collectors.

It is preferred to place an inter-collector insulating strip between the inlet collector and the outlet collector on both sides of the unit, separating the pipelines with various media of different physical state, with different temperatures.

In construction conditions with a horizontal location of the radiator plane, it is preferred that the inlet collectors in both heat exchangers be located above the outlet collectors.

In a further preferred embodiment, the surface between the outlet collectors of the two exchangers is covered by a counter-plate that adheres to the flow channels. The solution with a counter-plate made of a material with a low thermal conductivity coefficient, one-sidedly directs the heat transfer, is particularly useful for a horizontal unit, for example an ice-making device incorporated as an evaporator into the heat pump. The counter-plate made of a material with good thermal conductivity is the condition for two-sided radiation of heat from the flow channels, which is preferred with the vertical construction of the unit.

In the next improvement, pairs of the inlet collectors and outlet collector adjacent to each other on both sides of the unit are longitudinally covered by the edge thermal insulation.

Simultaneous incorporation of two similar harp exchangers into the heat pump circuit, with the flow channels located alternately in one plane and connected with a common radiator plate results in the fact that the thermodynamic medium in adjacent flow channels travels in opposite directions but with locally and longitudinally overlapping isotherms of the temperature field. As a result, a uniform temperature distribution occurs over the entire surface of the radiator plate. High efficiency of the heat exchange unit affects the reduction of overall dimensions. Furthermore, in the horizontal installation of the unit according to the invention, bending down towards the outlet collectors of the final sections of the flow channels causes the oil suspended in the thermodynamic medium - introduced through the compressor - to freely drip into the collector, which, in the next cycle of operation, significantly facilitates the start-up of the device.

A full understanding of the solution according to the invention makes it possible to describe an exemplary implementation of a heat exchange unit which is incorporated as an evaporator into the heat pump circuit in the device for manufacturing and storing ice. The unit is shown in the drawing, whose figures show:

Fig.1 - unit diagram

Fig.2 - unit in a perspective view,

Fig.3 - vertical cross-section through the axis of the flow channel of the first exchanger,

Fig. 4 and Fig. 5 - the middle fragments of the vertical cross-sections of two exemplary embodiments of the heat exchange surface, according to the line A- A in Fig. 2,

Fig.6 - a vertical cross-section of the unit according to the line C-C in Fig. 2 through the axis of the flow channel of the first heat exchanger, Fig.7 - a vertical cross-section of the unit according to the line D-D in Fig. 2 through the axis of the flow channel of the second heat exchanger,

Fig.8 - a vertical cross-section of the left side of the heat exchange unit, with a counter-plate and edge thermal insulation.

The heat exchange unit 1 consists of two similar tubular heat exchangers 2 and 3 incorporated simultaneously in the circuit of the thermodynamic medium of the heat pump. The unit can perform both the evaporator and condenser functions, working in horizontal or vertical positioning. Each of the exchangers 2 and 3 with a harp system has parallel inlet collector 7 and outlet collector 8 spaced apart. The collectors 7.1 and 8.1 of the first exchanger 2 and the collectors 7.2 and 82. of the second exchanger 3 are connected by numerous tubular flow channels 5,1 and 5.2 located perpendicular. Final sections 10.1 and 10.2 of flow channel connections 5.1 and 5.2 to the outlet collector 8.1 , 8.2 are deflected by a dimension (e) greater than half the sum of the outside diameters d1 of the inlet collector 7.1 and 7.2 and the diameter d2 of the outlet collector 8.1 and 8.2 - as shown in Fig. 3 of the drawing. With superimposing the exchangers 2 and 3, the inlet collector 7.1 of the first exchanger 2 and the outlet collector (8.2) of the second exchanger 3 are located parallel to each other on both sides of the heat exchange unit 1 and on the other side the inlet collector 7.2 of the second exchanger 3 and the outlet collector 8.1 of the first exchanger 2. The flow channels 5.1 and 5.2 are connected - while maintaining good thermal conductivity - by the plate of the radiator 4 made of a material with high thermal conductivity coefficient between the inlet collectors 7.1 and 7.2 of both exchangers 2 and 3. Tubular nozzle distributors 11 , having many nozzle orifices 12 on the side, directed coaxially to the inlets 13 of the flow channels 5.1 and 5.2, are introduced longitudinally to the inside of the inlet collectors 7.1 and 7.2. The diameters d3 of the nozzle orifices 12 increase successively from the end of the thermodynamic medium supply. Inter-collector insulating strips 14 which thermally separate the pipelines through which fluids of different temperatures flow are introduced on both sides of the unit between the inlet collectors 7.1 , 7.2 and the outlet collectors 8.1 , 8.2. In conditions shown in Fig. 6 and 7 and with horizontal installation of the heat exchange unit, the inlet collectors 7.1 and 7.2 in both heat exchangers 2 and 3 are arranged above the outlet collectors 8.1 and 8.2. Fig. 8 shows the implementation of the unit incorporated into the heat pump circuit as an evaporator, installed horizontally, where the surface between the outlet collectors 8.1 and 8.2 of both exchangers 2 and 3 is covered by a counter-plate 6 of thermally insulating material. Grooves including the flow channels 5.1 and 5.2 are performed in the counter-plate 6, which allows the counter-board 6 to adhere to the plate of the radiator 4. Using the unit in the ice-making device is supplemented by the incorporation of edge thermal insulations 15, comprising pair of the inlet collectors 7.1 , 7.2 and outlet collectors 8.2, 8.1 adjacent longitudinally to each other on both sides. In the operation of the device - uniformity of temperature over the entire surface of the radiator, obtained as a result of local equalization of the amount of heat supplied to the radiator by contiguous counter-current flows of thermodynamic media in the phases of physical transition with a constant parameter difference - is essential for the production efficiency and storage capacity of the ice in the device.

List of indications in the figure

1. heat exchange unit

2. first heat exchanger

3. second heat exchanger

4. plate of the radiator

5. flow channels

5.1 flow channels of the first exchanger

5.2 flow channels of the second exchanger

6. counter-plate

7. inlet collector

7.1 inlet collector of the first exchanger

7.2 inlet collector of the second exchanger

8. outlet collector

8.1 outlet collector of the first exchanger

8.2 outlet collector of the second exchanger

9-9 radiator plane

0. flow channel final section

10.1 flow channel final section of the first exchanger

10.2 flow channel final section of the second exchanger 1. tubular nozzle distributor

2. nozzle orifice

3. flow channel inlet

4. inter-collector insulating strip

5. edge thermal insulation e. the dimension of the inlet collector offset relative to the outlet collector d1. outside diameter of the inlet collector

d2. outside diameter of the outlet collector

d3. diameter of the nozzle orifice

k. the flow direction of the thermodynamic medium