0.0 VAPOUR ABSORPTION CHILLING UNIT 0.1 The unit shall be two stage/double effect direct fired machine of hermetic design, completely factory assembled and leak tested, working on Lithium Bromide as absorber and water as refrigerant. Refrigerant generator shall be natural gas fired. 0.2 Unit shall consist of high temperature and low temperature generator, evaporator, absorber, condenser, high temperature heat exchanger, low temperature heat exchanger, eliminators, solution pump, refrigerant pump, purge and all interconnecting piping and accessories. 0.3 Material of construction of high temperature generator shall be as follows: a) Furnace/Shell/Tube sheet – Boiler quality plate SA 515/516 Gr.70. b) Tubes – Seamless Tubes BS-3059 Part-I. 0.4 Condenser, absorber and evaporator tubes shall be of seamless copper. All tubes shall be individually replaceable at either end of the machine. Headers shall be removable for free access to the tube bundles. Evaporator, condenser and absorber water circuit and headers shall be designed for working pressure of 10.5 Kg/cm2. All headers shall be tested as 1.5 times of their design pressure. 0.5 Unit shall be equipped with canned pump motor assemblies factory mounted, wired and tested for the refrigerant and solution circuits. Pumps shall be designed for low net positive suction head and heavy-duty services. Material of construction shall be suitable of with standing the corrosive solution of lithium bromide and water. 0.6 Units shall be equipped with purge system consisting of an electrically motor driven vacuum pump. The system shall have sufficient capacity to purge the unit of noncondensable gases in a period of not more than one hour during normal machine operation. 0.7 Unit shall be be equipped with automatic capacity control for operation from 100% to 20% of machine rated capacity. The control shall be stepless type. 0.8 Fouling factor of chilled water circuit shall be 0.0001 and of condenser water circuit shall be 0.0002 in metric units. 0.9 Thermometer wells shall be provided at following places: a) Chilled water inlet and outlet piping. b) Condenser water inlet and outlet piping. c) Condenser water crossover piping between absorber and condenser. 0.10 Sight glasses shall be provided to monitor solution level at following places: a) Evaporator. b) High temperature generator shell. c) Absorber shell.
0.11 Unit shall be equipped with safety develop including but not restricted to the following: a) Flame Failure Protection: i) Flame detector and protect relay, to stop the machine, in case of flame failure. ii) Air flow switch, to stop the machine, in case of decrease in the pressure of blower. iii) High gas pressure switch, to stop the machine, in case of increase of gas supply pressure. iv) Low gas pressure switch, to stop the machine, in case of decreases of gas supply pressure. b) Chilled Water Freeze Protection: i) Chilled water flow switch is stop the machine when the chilled water flow is less than 50% of the specified flow. ii) Antifreeze thermostat to stop the machine when the chilled water temperature is less than 0.5oC. iii) Pump interlock to prevent start/run of the machine without the pump working. c) Motor Protection: Over current relays for absorber/refrigerant/purge pumps and burner blower to stop the machine in case of over currents. d) Generator Protection and Crystallisation Protection: i) Chilled water flow switch is stop the machine when the chilled water flow is less than 50% of the specified flow. ii) Generator temperature controller to stop the machine at 160oC. iii) Exhaust gas thermostat to stop the machine at 300oC. iv) Generator solution level relay with electrodes to stop absorber pump when the solution level reaches the specification point E1. 0.12 Unit shall be equipped with local control panel which shall include but not restricted to the following: a) Terminal blocks for power and control interlocks. b) All necessary switches, fuses, starters, controls, transformers and relays. c) Start and stop buttons/switches. d) Indicator lights for visual indications of machine operation mode. e) Indicator warning lights for safety indication. f) Warning alarm bell. g) High pressure switches. h) Solution level limit electrodes. i) First stage generator, high temperature limit switches. j) On line purging system and purge storage tank connected with purge pump.
0.13 Testing: Following tests shall be conducted at works prior to despatch, in presence of the OWNER’s representative: a) Checking of all physical dimensions. b) Hydraulic pressure test. c) Helium leak testing. d) Unit Capacity Test: Refrigerant capacity shall be computed from the temp. reading & water flow measurements shall be through flow meters. Computed results shall tally with the specified capacities and those furnished by the contractor. e) Gas Consumption Test: Consumption of natural gas shall be calculated by observing difference in meter readings over a predetermined time period. Specific consumption shall be calculated by recording the refrigeration capacity during the same period. The results should establish that the consumption is not exceeding the figures committed by the contractor. f) All instruments, services needed for the tests required for the computation of capacities and power consumption shall be furnished by the contractor. All instruments shall be calibrated and the contractors shall produce calibration certificates. g) Contractor shall furnish detailed certificates of the tests carried out on Test Bed in his factory. Test certificates shall essentially contain the results of continuous eight (8) hours operation at full load for all the rated parameters. 0.14 Insulation: After installation and commissioning of the unit at site, the unit shall be insulated with cold and hot insulation material of appropriate thickness on the respective surfaces of the unit.
TECHNICAL DATA SHEET- STEAM FIRED 0.0 VAPOUR ABSORPTION CHILLING UNIT: 0.0 Chilled Water Circuit -Refrigeration Capacity (TR) -Chilled water flow (M3/Hr) -Chilled water temperature: Inlet (oC) Outlet (oC) -Fouling factor (British)
: _______________ : _______________ : _______________ : _______________ : _______________
0.0 Cooling Water Circuit -Cooling water flow rate (M3/Hr)
: _______________
-Cooling water temperature: Inlet (oC) Outlet (oC) -Fouling factor (British)
: _______________ : _______________ : _______________
0.0 Steam -Pressure of steam (min. required) (Kg/cm2) -Steam temperature (oC) -Steam consumption (Kg/hr)
: _______________ : _______________ : _______________
0.0 Electrical Ratings -Absorbent Pump (KW) -Refrigerant Pump (KW) -Vacuum Pump (KW) -Other Motors (pl. specify) (KW)
: _______________ : _______________ : _______________ : _______________
0.0 Physical Data -Length (MM) -Width (MM) -Height (MM) -Shipping weight (Tons) -Operating weight (Tons) -Space for tube cleaning (MM)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________
0.0 High Temperature Generator -Shell Material -Tube Material -Type of Tubes -Tube I.D./O.D./Base thickness (MM) -Length of tube (MM) -Type of tube joints (Welded/Expanded)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________
0.0 Low Temperature Generator -Shell Material -Tube Material -Type of Tubes -Tube I.D./O.D./Base thickness (MM) -Length of tube (MM)
: _______________ : _______________ : _______________ : _______________ : _______________
0.0 Condenser -Shell Material -Tube Material -Type of Tubes -Tube I.D./O.D./Base thick./O.D. (Fin) (MM) -Length of tube (MM) -Cooling water flow rate (M3/hr) -No. of Passes (Nos)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________
-Preessure Drop (Kg/cm2) -Temperatue in/out (oC) -Fouling factor (British)
: _______________ : _______________ : _______________
0.0 Evaporator -Shell Material -Tube Material -Type of Tubes -Tube I.D./O.D./Base thick./O.D. (Fin) (MM) -Length of tube (MM) -Cooling water flow rate (M3/hr) -No. of Passes (Nos) -Preessure Drop (water side) (Kg/cm2) -Temperatue in/out (oC) -Fouling factor (British)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________
0.0 Absorber -Shell Material -Tube Material -Type of Tubes -Tube I.D./O.D./Base thickness (MM) -Length of tube (MM) -Cooling water flow rate (M3/hr) -No. of Passes (Nos) -Preessure Drop (Kg/cm2) -Temperatue in/out (oC) -Fouling factor (Metric)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________
0.0 High Temperature Heat Exchanger -Shell Material -Tube Material -Type of Tubes -Tube I.D./O.D./Base thick./O.D. (Fin) (MM) -Length of tube (MM) -No. of Passes on shell side (Nos) -No. of Passes on tube side (Nos)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________
0.0 Low Temperature Heat Exchanger -Shell Material -Tube Material -Type of Tubes -Tube I.D./O.D./Base thick./O.D. (Fin) (MM) -Length of tube (MM) -No. of Passes on shell side (Nos) -No. of Passes on tube side (Nos)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________
0.0 Purge Unit -Make & Model -Purging is constant or intermittant? -Type of Vacuum Pump -Capacity (M3/hr) -Differential head (MM Hq.)
: _______________ : _______________ : _______________ : _______________ : _______________
-Any anti-sucj back device provided? -Power consumption (KW) -Motor rating & speed (KW/RPM) 0.0 Refrigerant Pump -Material of Shaft, Impeller & Casing -Type of Pump -Make & Model -Nos. of Pump used -Capacity (M3/hr) -Head (M) -Power consumption (KW) -Motor rating & speed (KW/RPM) -Any provision for measurement of bearing wear & tear by transducer (Yes/No) -Type of cooling of the pump -Working fluid -NPSH Requirement (M WC)
: _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________ : _______________
