Patent Publication Number: US-2023147460-A1

Title: Solar integrated chiller method and system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/071,332 filed Jul. 19, 2018 which is a National Entry Application of PCT application No. PCT/CA2017/050070 filed on Jan. 24, 2017 and published in English under PCT Article 21(2), which itself claims benefit of US provisional application Ser. No. 62/286,824, filed on Jan. 25, 2016. All documents above are incorporated herein in their entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to chillers. More specifically, the present invention is concerned with a solar integrated chiller, method and system. 
     SUMMARY OF THE INVENTION 
     More specifically, in accordance with the present invention, there is provided a system comprising at least one AC condenser fan; at least one solar panel; at least one AC/DC convertible fan connected to the at least one solar panel; and a controller configured to determine when sufficient DC power is available and activating the at least one AC/DC convertible fan when sufficient DC power is available, and when DC power is not sufficient, activating the at least one AC condenser fan. 
     There is further provided a method for powering an air cooled oil-free centrifugal chiller system comprising condensers, at least one AC/DC convertible fan and at least one DC fan, the method comprising providing at least one solar panel and connecting the AC/DC convertible fan to the at least one solar panel; determining i) when sufficient DC current generated by the solar panel is available and then running the AC/DC convertible fan, and ii) when the solar-generated DC current is not sufficient, running the DC fan. 
     There is further provided a method for directly powering a AC/DC convertible fan of an air cooled oil-free centrifugal chiller using DC solar-generated current, comprising providing at least one solar panel and a controller; connecting the AC/DC convertible fan to the at least one solar panel; determining, by the controller, i) when sufficient DC solar-generated current is available and then running the AC/DC convertible fan, and ii) when sufficient DC solar-generated current is not available, running the AC/DC convertible fan using a battery bank. 
     Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings. 
     Description 
       
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the appended drawings: 
         FIG.  1    is a perspective view of a system according to an embodiment of an aspect of the present invention; 
         FIG.  2    is a side view of the system of  FIG.  1   ; 
         FIG.  3    is a perspective view of a system according to an embodiment of an aspect of the present invention; 
         FIG.  4    is a side view of  FIG.  3   ; 
         FIG.  5    is a side view of a system according to an embodiment of an aspect of the present invention; 
         FIG.  6    is a side view of a system according to an embodiment of an aspect of the present invention; 
         FIG.  7    is a top view of the system of  FIG.  6   ; 
         FIG.  8    is a side view of a system according to an embodiment of an aspect of the present invention; 
         FIG.  9    is a perspective view of the system of  FIG.  8   ; 
         FIG.  10 A  is a schematic view of a system according to an embodiment of an aspect of the present invention; 
         FIG.  10 B  shows a detail of  FIG.  10 A ; 
         FIG.  10 C  shows a detail of  FIG.  10 A ; 
         FIG.  10 D  shows a detail of  FIG.  10 A ; 
         FIG.  10 E  shows a detail of  FIG.  10 A ; 
         FIG.  10 F  shows a detail of  FIG.  10 A ; 
         FIG.  10 G  shows a detail of  FIG.  10 A ; 
         FIG.  11 A  is a top view of the system of  FIG.  10   ; 
         FIG.  11 B  is a first side view of the system of  FIG.  10   ; 
         FIG.  11 C  is a second side view of the system of  FIG.  10   ; 
         FIG.  12 A  is a first view of a bracket according to an embodiment of an aspect of the present invention; 
         FIG.  12 B  is a second view of the bracket of  FIG.  12 A ; 
         FIG.  13 A  is a first view of a bracket according to an embodiment of an aspect of the present invention; 
         FIG.  13 B  is a second view of the bracket of  FIG.  13 A ; 
         FIG.  14    is a diagrammatic view of a method according to embodiments of an aspect of the present invention; and 
         FIG.  15    is a diagrammatic view of a system according to an embodiment of an aspect of the present invention. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The present invention is illustrated in further details by the following non-limiting examples. 
     An air cooled oil-free centrifugal chiller typically comprises condenser fans (C). 
     As illustrated for example in  FIGS.  10 A and  11 C , an array (A) of solar panels is mounted above the condenser fans (C), at a distance from the top edge of the condenser fans, for example at a minimum height H of 450 mm above the top surface of the condenser fans, at an angle in a range between about 15 and 40° from the horizontal, for example at an angle of about 15° from the horizontal, depending upon the geographical position and time of the year, i. e. for best incidence of sun rays on the solar panels, i.e. incidence at an angle between about between 37° and about 45° for example. 
     The solar panels are positioned relative to the condenser fans (C) using posts  14  supported by the ground (see for example  FIGS.  1 - 3 ,  5 ,  10  and  11   ) or using posts  16  supported by the fan casing  18  itself (see for example  FIGS.  6 - 9   ). Alternatively the solar panels may be connected to the fan casing  18  itself (see for example  FIG.  4   ). Mounting brackets  15 , 17  as illustrated for example in  FIGS.  12 - 13    are used, as best seen in  FIG.  10   . 
     At least one, for example two, of the condenser fans comprises a motor than can run on either DC or AC power and these DC/AC motors are connected to the solar array. The remaining condenser fans run on AC power only. When DC power is available, these condenser fans that can run on either DC or AC power run before any of the AC-only driven condenser fans (see  FIG.  15   ). 
     The system comprises a controller  20  that determines when sufficient DC power is available to run the fans. When DC power is not sufficient, the controller  20  switches to allow AC power to be delivered to the fan motors. The controller  20  also determines that when the chiller is not called on for duty and DC power is available, the power is interrupted until the chiller is called to run. 
     A battery bank, as shown in  FIG.  14   , may be used to power the condenser fans over short period of times, for example during passage of clouds covering the sun, thereby providing a buffer period during which there is no switch from DC to AC powering of the fans. 
     A measure of chiller efficiency based as developed by the Air-Conditioning, Heating and Refrigeration Institute (AHRI) is the Integrated Part Load Value (IPLV), most commonly used to describe the performance of a chiller capable of capacity modulation. Unlike an EER (Energy Efficiency Ratio) or COP (coefficient of performance), which describes the efficiency at full load conditions, the IPLV is derived from the equipment efficiency while operating at various capacities. Since a chiller does not always run at 100% capacity, the EER or COP is not an ideal representation of the typical equipment performance. The IPLV is a very important value to consider since it can affect energy usage and operating costs throughout the lifetime of the equipment. Using a system of the invention comprising an array of 15 solar panels (3×5) mounted above the condenser fans at a minimum height of 450 mm above the top edge of the condenser fans, and two of the condensers of 6 comprising a motor which can run on either DC or AC power (see  FIGS.  10 - 11   ), during sunshine hours, i.e. when solar power replaced AC to these two fans, the IPLV was shown to be improved by as much as 15%. A typical condenser fan motor consumes 2.1 kW at full load. The system with the solar array produced up to 4.2 kW. During part load situations, the fan power could be fully displaced at 25% load. On sunny days in low ambient conditions, free cooling can be added automatically, further reducing power requirements in winter. 
       FIG.  14    shows a battery bank to store energy to run the fans during short periods of time when cloud cover prevents the solar array (A) from operation for example. This time period is dependent of the amount of batteries used, typically one hour for example. Moreover, the battery bank can provide DC voltage to the building if the chiller is not in use. 
     The present method and system provides using DC solar-generated current to directly power AC/DC convertible fans. Up to 15% efficiency increase has been recorded in prototype test when solar power replaces AC to two fan arrays. Payback of the solar addition can be as little as 12 months in sunny locations with power costing 24c/kWh. On sunny days in low ambient conditions, free cooling can be added automatically, further reducing power requirements in winter. 
     In high density cities with high rise buildings that include residences located close to an air cooled chiller, the noise levels can be so high that it can have an adverse effect on residents. By placing the present solar array above the main noise source, i.e. the condenser fans, the present system and method provide a noise abatement ability to lower noise affects. 
     Because the solar array is designed to overhang the condenser coils of the chiller, a shading affect occurs thus improving the heat transfer by the air passing over the condenser coils thus improving the chiller efficiency. Thus, the mounting of photovoltaic panels in a canopy adds weather protection and enhances aerodynamic efficiency of fan exhausts (see for example  FIG.  15   ). 
     Currently today, all solar photovoltaic systems require inverters, utility grid protection equipment and sometimes battery systems. The present system is a direct-connect to the AC/DC fan motors thus eliminating the need for an inverter and utility grid protection equipment. 
     Typical back side temperatures on the solar panels are above 125 F. As back side temperatures are reduced, the panel efficiency improves. Since the solar array is mounted above the condenser fans, the air temperature from the condenser fans is kept under 115 F maximum thus providing a 10 degrees improvement and thus improving panel temperatures. 
     Further consideration may be to place a thermal heat recovery system on the back side of the solar panels for pre-heating domestic hot water systems for example. For example, the solar array can be equipped with a hot water heat recover system on the back side of the panels, which allows for pre heating domestic hot water. This system requires a water pump with piping and valves. The water flows through the panels and the heat from the sun provides water between 130 and 140° F. 
     The present combination forms an integrated system that uses solar power to drive condenser fans which are part of an air cooled oil-free centrifugal chiller. 
     The present system and method allows use of solar power when available without AC/DC conversion. 
     The scope of the claims should not be limited by the embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.