AU2013100041A4 - A Solar Assisted Chiller System - Google Patents

Abstract

Abstract This invention reduces the cost of operating refrigeration systems for cold rooms or chillers utilising solar thermal boosting.

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT A SOLAR ASSISTED CHILLER SYSTEM The following statement is a full description of this invention, including the best method of performing it known to me: @Ross Hastings 2012 A Solar Assisted Chiller System Technical Field of the Invention: 5 This invention relates to compressed vapour chiller and cold room systems, and in particular but not limited thereto, the invention relates to a solar assisted chiller system. Background of the Invention: Known compressed vapour chiller systems use a combination of compressor, condenser and evaporator to generate the cooling effect needed in the chiller. 10 The system produces a cooling effect by condensing a refrigerant with a suitable due point and then allowing it to expand and evaporate through a restrictive device such as a capillary or a TX valve and transferring the resultant cooling effect to the space to be chilled by using a fan. Electrical or mechanical energy is used to drive the compressor required to circulate the 15 refrigerant and assist in the condensation of the refrigerant. This is a relatively inefficient use of such energy sources as the compressor is required to run for long periods and in some cases continuously. Object of the Invention: Therefore the object of this invention is to reduce the operating time of the compressor by 20 improving the efficiency of condensation. Summary of the Invention: In one aspect therefore the present invention resides in a solar chiller system that uses a solar thermal collector panel or solar concentrator to collect thermal energy in the form of solar heated water that can be stored efficiently in a well insulated hot water storage tank. 25 In another form of the art, any low grade heat source may be used in place of the solar thermal collection system. The storage tank may be constructed using a double glazed mild steel inner tank with polyurethane insulation surrounded by a galvanised steel outer casing. The tank may also use a wound pipe to allow heat exchange to occur between the stored water and the chiller 30 refrigerant. The heat exchange may be arranged to reside between the compressor and the condenser in the said chiller system. The purpose of the heat exchange is to heat and expand the refrigerant after it has been compressed and before it enters the condenser coil. 11 I The addition of the solar thermal energy increases the temperature and pressure of the refrigerant so that when it enters the condenser coil,. the difference between the ambient 35 temperature of the cooling medium(in this case ambient air), and the refrigerant is greater. The condensation process is enhanced so that the phase change from vapour to liquid is more thoroughly accomplished. This results in a change in the operating cycle of the compressor reducing the time that the compressor is required to run. 40 Brief Description of the Drawings: Figure 1 is a schematic drawing of the operation of a solar chiller system. Figure 2 is a layout of the components of a solar chiller system. Detailed Description of the Drawings: Referring to figure 1, there is a schematic of the solar assisted chiller system. 45 The compressor pumps refrigerant(1), into the heat exchange coil in the solar thermal storage tank where it is expanded and heated using solar thermal energy rolled over from the stored solar heated water. The solar heated refrigerant is then passed into the condenser(2), where the ideal conditions for condensation promote the thorough phase change of the refrigerant from gas 50 into liquid. This liquid is then applied to the metering device or capillary(3), before the liquid line delivers it to the evaporator coil where the phase change of the refrigerant from liquid to vapour supplies the cooling energy to chill the air(5), being pumped by the fan into the area to be chilled(6). 55 The refrigerant vapour returns to the compressor(4), via the vapour line to repeat the cycle. Referring to Fig 2, a solar thermal collection system, A, may comprise a flat plate, heat pipe or parabolic dish solar collection system. Water from the lowest port in the storage tank, B, is pumped through the solar collection system. 60 The flow rate is controlled by a differential controller that is able to determine the comparative temperature of the water in the storage tank and the solar collector and operate a circulation pump when the solar collector temperature is higher than the storage tank temperature. Refrigerant is pumped by the compressor, C, into the heat exchange coil, F, in the storage 65 tank where the thermal energy is rolled over from the stored hot water. 2 1 P The heated refrigerant then enters the condenser coil, D, where it is condensed into fluid by the combination of cooling and pressure. The condensed refrigerant is then choked by a capillary or TX valve before it is piped to the fan coil, E, in the area to be chilled. 70 In another form of the art, the condensed refrigerant is applied to a heat exchanger within the body of the compressor/condenser case where the cooling effect is transferred to a fluid that may comprise water and propylene glycol. This fluid is then pumped to the heat exchanger in the fan coil to cool the required area. This method reduces the volume of refrigerant required by the system. 75 Summary In this form of the art the condenser operation is enhanced by the increased temperature and pressure of the refrigerant caused by the thermal energy gathered in the heat exchanger in the thermal storage tank. 80 The desired result is that the compressor operation cycle is altered significantly such that the energy consumed is greatly reduced. Whilst the above has been given by way of illustrative example of the present invention many variations and modifications thereto will be apparent to those skilled in the art 85 without departing from the broad ambit and scope of the invention as herein set forth in the following claims Inventor: Ross Hastings 3 | P