Saving energy by solar collector and heat pump combination in hot water production in residential and hotel sectors Dr. Nguyen Nguyen An, HUST
CONTENTS Energy consumption to produce hot water in residential and hotel sectors Current solutions to save energy in hot water production Solar collector and heat pump combination in hot water production (SHCS Solar & Heat pump Combination System) Some achievements of SHCS project Conclusions
Energy consumption to produce hot water in Vietnam Residential Energy Consuption in Vietnam Hotel Energy Consumption in Vietnam Air conditioning 45% Others 10% Lighting 27% Hot water 18% Lighting Hot water Air conditioning Others Air conditioning 50% Lighting 20% Hot water 30% Lighting Hot water Air conditioning
Energy consumption to produce hot water in other country
Energy consumption to produce hot water
Current solutions to save energy in hot water production Using solar collector: zero energy consumption but strongly influenced by weather condition. Using hot water heat pump (HWHP): low energy consumption (about 1/3 of resistant element water heater) but required regularly maintenance. Using both solar collector and HWHP: working non-influenced by weather, almost zero energy consumption, requirement of regularly maintenance will be reduced but required high initial cost.
Solar collector and Heat pump Combination System - SHCS Main ideas of SHCS project: Reduce the heating capacity (so reduce the initial cost) of the HWHP by increasing the volume of the hot water storage tank. Develop an intelligent controller that can automatically operate the HWHP based on the amount of hot water required by the load in future. Currently, the HWHP controller works based on the set temperature only. Develop a design tool (dynamic simulation basic) which can determine the heating capacity of the HWHP from weather data analysis and the pattern of hot water load.
Solar collector and Heat pump Combination System - SHCS Goals of SHCS project: Design, install and test a prototype of SHCS to produce hot water for a 5-person house in Vietnam. Design, install and test a prototype of SHCS to produce hot water for a 220-room, 4-star hotel in Vietnam. Develop a controller algorithm for SHCS. Develop a Computer Aided Design (CAD) software for SHCS.
Some achievements of SHCS project
Prototype of SHCS to produce hot water for a 5- person house in Vietnam Diagram of SHCS
Prototype of SHCS to produce hot water for a 5- person house in Vietnam System specifications: - Location: Hanoi capital - Total volume of hot water storage: 250 liters - Solar collector type: vacuum tube, D58 mm - Number of vacuum tube: 20 - Absorption area of solar collector: 2.64 m 2 - Heating capacity of HWHP: 950 W (20.4% of usual requirement of 4.65 kw) - Heating COP: 3.25 - Daily hot water usage: 150 liters
Prototype of SHCS to produce hot water for a 5- person house in Vietnam Solar collector: - Type: vacuum tube, D58 mm - Number of vacuum tube: 20 - Absorption area: 2.64 m 2 - Volume of storage tank: 200 liters
Prototype of SHCS to produce hot water for a 5- person house in Vietnam Cycle diagram of HWHP:
Prototype of SHCS to produce hot water for a 5- person house in Vietnam 1 st Prototype of HWHP - Compressor: Danfoss, Model SC-10GH, Refrigerant R134a, S.V. 10.29cm 3 /rev. - Evaporator: finned tube type - Condenser: Helical shape heat exchanger with natural convective on water side, HE area 0.226 m 2 - Expansion device: capillary tube - Volume of storage tank: 50 liters
Prototype of SHCS to produce hot water for a 5- person house in Vietnam 2 nd Prototype of HWHP - Compressor: Danfoss, Model SC-10GH, Refrigerant R134a, S.V. 10.29cm 3 /rev. - Evaporator: finned-tube type - Condenser: Helical shape heat exchanger with natural convective on water side, HE area 0.32 m 2 - Expansion device: capillary tube - Volume of storage tank: 50 liters
Prototype of SHCS to produce hot water for a 5- person house in Vietnam 950 W condenser manufacture for 2 nd Prototype - Condenser type: Helical shape with natural convective on water side - Outside diameter of coil: 90 mm - Height of coil: 550 mm - Number of revolution: 64 - Total heat exchanger area: 0.32 m 2
Prototype of SHCS to produce hot water for a 5- person house in Vietnam 2 nd Prototype of HWHP, Final installation
Prototype of SHCS to produce hot water for a 220-room, 4-star hotel in Vietnam Diagram of SHCS
Prototype of SHCS to produce hot water for a 220-room, 4-star hotel in Vietnam System specifications: - Location: Nha Trang city - Total volume of hot water storage: 30 m 3 (variable volume) - Solar collector type: vacuum tube, D58 mm - Number of collector panel: 27 - Number of vacuum tube per panel: 50 - Total absorption area of collector panels: 186 m 2 - Number x Heating capacity of a HWHP: 4 x 18.5 kw - Total heating capacity of HWHP: 74 kw (34.7% of usual requirement of 213 kw) - Heating COP: 3.6 - Daily hot water usage: 13.2 m 3
Prototype of SHCS to produce hot water for a 220-room, 4-star hotel in Vietnam Cycle diagram of HWHP: - Compressor: Bitzer, 4CC-9.2Y, R134a, 370cm 3 /rev. - Evaporator: finned-tube type - Condenser: shell-tube, multi body heat exchanger type - HE area: 2.51 m 2 - Expansion device: thermostatic expansion valve (Danfoss)
Prototype of SHCS to produce hot water for a 220-room, 4-star hotel in Vietnam 18.5 kw condenser manufacture (total HE area 2.51 m 2 ): - Diameter of shell (outer tube): 54 mm - Number of shell per heat exchanger: 10 - Diameter of tube: 12.7 mm - Number of tube per shell/ per heat exchanger: 7/70
Prototype of SHCS to produce hot water for a 220-room, 4-star hotel in Vietnam 1 st Prototype of HWHP: - Height: 1450 mm - Width: 1135 mm - Depth: 550 mm
Prototype of SHCS to produce hot water for a 220-room, 4-star hotel in Vietnam 1 st Prototype of HWHP: - Height: 1450 mm - Width: 1135 mm - Depth: 550 mm
Conclusions Method proposed for saving energy in hot water production in residential and hotel sectors can provide hot water with very low energy consumption. This method can be implemented with reasonable initial cost by reducing the heating capacity of Hot Water Heat Pump (HWHP) down to 20.4% and 34.7% for residential and hotel sectors, respectively. Require further study to verify the HW supplying capability as well as to determine the payback period of this method with various applications.
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