Lecture # 7 Min soo Kim Mechanical & Aerospace Engineering Environmental Thermal Engineering Lecture # 7 Min soo Kim Mechanical & Aerospace Engineering

Operating characteristics and Application of Heat pump systems

Heat Pump Cycle Heat absorption from cold reservoir and heat transport to hot reservoir Same organization with existing refrigerating cycle Use for both heating and cooling Highly economical in initial installation cost and space Switch the role of indoor and outdoor heat exchanger by changing the flow direction depending on operation purpose(heating, cooling) Use four way valve in order to change flow direction

Compare Energy Flow Diagram Electric Heating instrument Boiler Heat Pump

Compression Heat Pump for heating and cooling Outdoor unit heat exchanger Accumulator Compressor Motor Oil-separator 4-way Valve Bypass Valve Expansion Valve Indoor unit Heating Mode Cooling Mode

Heat Pump Classification(1) The method of heat pump classification 1) Heat source and sink 2) Transfer medium of heating and cooling energy 3) The form of building structure 4) Size and appearance Heat source of heating heat pump Air, well water, groundwater and geothermal, solar and other natural heat source, waste heat coming out of swimming pool, commercial building, etc.

Heat Pump Classification(2) Heat source and sink Distribution fluid Thermal cycle schematics Air Refrigerant changeover Water

Heat Pump Classification(3) Heat source and sink Distribution fluid Thermal cycle schematics Water Water changeover Ground-coupled Air Refrigerant changeover Ground-source, Direct-expansion

Heat Pump Operating Characteristics(1) Heating capacity and load of heat pump depending on the change of outdoor temp.

Heat Pump Operating Characteristics(2) Outdoor temp. drop 1. Less heat pump capacity than required heating load i) Use additional heating equipment Reduction in overall efficiency of heat pump ii) Use large heat pump or inverter 2. Frost formation on the surface of outdoor coil : decrease in heating capacity, causing the liquid refrigerant to compressor Prevent decline of efficiency and heating capacity by increasing the temp. of evaporator using waste heat, river water, well water, etc.

Heat Pump Operating Characteristics(3) Heat pump performance depending on outdoor temp. Capacity (103 Btu/hr) Air Temperature (oF) Power (kW) Air Temperature (oF)

General Vapor Compression Heat Pump QH High pressure liquid High pressure High temperature vapor Condenser Compressor Expansion device W Low pressure Low temperature Mixture of liquid & vapor Evaporator QL

Thermodynamics in Heat Pump Indoor supply heat= Outdoor heat + Compressor electrical work COP of heating mode = heat effect and input power proportions COP of heating mode = heat effect and overall electrical input power proportions COP of cooling mode

COP of Cooling Mode Capacity & COP Operation mode Heat absorbed by evaporator Work input to compressor Heat rejected by condenser COP Heating Cooling 1 0.3 1.3 4.3 3.3

Economics on Heat Pump Operation(1) Annual residential heating load Total electric energy required for heat pump Power plant efficiency Hot air furnace plant efficiency Amount of resources required for heat pump Amount of resources required for hot air furnace If Power plant efficiency is 0.35 and Hot air furnace efficiency is 0.85, Cop is higher than 2.4

Economics on Heat Pump Operation(2) Electric charge Fuel cost per unit calorie Heat pump operating cost < Hot air furnace operating cost

The world Heat Pump Operating Temp. Range Zone 1 : year round cooling Twinter ≥ 20℃ Tsummer ≥ 20℃ Zone 2 : heating and cooling Twinter ≥ 0℃ Tsummer ≥ 20℃ Zone 3 : cooling in summer Twinter ≤ 0℃ Tsummer ≥ 20℃ Zone 4 : heating in winter Twinter ≥ 0℃ Tsummer ≤ 20℃

Gas Engine Driven Heat Pump Background of Development Promote the use of alternative energy Efficient use of energy Suppress the power consumption in summer Averaging annual load of gas and electricity Patterns of consumption of gases & electricity (2005’) Power MAX.(MW) Gases (thousand.toe) Gas Engine Driven Heat Pump Drive compressor driven using gas engine Increase system efficiency by waste heat recovery Supplement the heating capacity decreases using waste heat depending on outdoor temp. decrease Defrost operation is not required and start-up characteristic is fast in heating mode Fuel diversification, low NOx Tue, small size, low noise, etc. is required.

Gas Engine Driven Heat Pump Cooling and Heating Cycle of Air-preheating GHP system

Solar Heat Driven Heat Pump Solar heat is usable only in daytime, so heat storage tank is needed. When we use solar heat collector as a radiator at night, cooling mode is possible. Composed of compressor, storage tank and solar collector

Solar Heat Driven Heat Pump Heating Cycle Cooling Cycle

Solar Heat Driven Heat Pump NASA contract NAS-97113, Johnson Space Center Synopsis: Variable Speed Solar Photovoltaic Heat Pump Compressor. Proof of concept to demonstrate a solar heat pump for advanced missions such as a lunar missions while at the same time, promoting commercialization of the technology for terrestrial applications.

Stirling Engine Driven Heat Pump High heat-efficiency Possible to use different kinds of fuels and heat sources Low problems of emissions, noise and vibration Resolve matters Regenerator efficiency increase Reliability secure of piston

Stirling Engine Schematic representation of the Stirling cycle in 4 steps: 1. The piston rises, the working gas is compressed. 2. The gas is displaced from the cold chamber to the hot chamber, the pressure increases further. 3. The piston falls, the gas is expanded. 4. The gas is displaced from the hot chamber to the cold chamber, the pressure decreases further.

Application of Stirling Engine Stirling-Rankine Fuel-Fired Heat Pump

Heat Pump using Heat Storage Fig. heating and cooling heat pump using heat storage

Heat Pump using Heat Storage

Lab Activities Multi-type Heat pump

Multi Type Heat Pump System The increasing demand for home HVAC Multi type HVAC One outdoor heat exchanger Several indoor heat exchanger Multi type heat pump system Saving cost and space Summer : Cooling systems Winter : Heating systems The problem of the complexity of the system and the capacity control

Multi Type Heat Pump for Building Outdoor Heat Exchanger Refrigerant Pipe Indoor Heat Exchanger

Advantages of Multi Type Heat Pump for Building Building Purpose Advantages A building for rent -Individual response to each residential room. - Clarification of residential air-conditioning usage fees. A office building -Respond to the loads from Small rooms (living room, conference room, etc.) to large rooms (longer serve space). -Economical Driving -Respond to the requirement of cooling and heating from Perimeter and interior zones. A intelligent building -Annual cooling respond to communication and OA equipment -Respond in case each room and store need cooling and heating at the same time. Hotel -Individual respond to each zone depending on different load characteristics. Hospital -Individual control of hospital room, nursing room, etc. Shopping center -Individual control of each store when business hours are different .

Schematic Diagram of Heating and Cooling Multi Type Heat Pump Indoor unit Service Valve Outdoor unit Indoor unit heat exchanger 1 Bypass Valve 4-way Valve Oil-separator Indoor unit heat exchanger 2 Compressor Accumulator Outdoor unit heat exchanger Service Valve Expansion Valve Motor Indoor unit heat exchanger 3 Accumulator Heating Mode Cooling Mode

Multi Type Heat Pump – Foreign Country Sanyo: 97’ Attempt new refrigerant to multi type air conditional Eco Multi System Daikin: Super Multi Plus product Mitsubishi Electronic: Y, R2 and WR2 series Toshiba: Super Multi product for R407C and R22

Multi Type Heat Pump – in the country LG Electronics Capacity - Cooling - 1unit(A) 11,000Btu/hr Capacity - Heating - 1unit(A) Capacity - Cooling - 2unit(B1+B2) 18,000Btu/hr Capacity - Heating - 2unit(B1+B2) Capacity - Cooling - 1unit(B1 or B2) 9,000Btu/hr Capacity - Heating - 1unit(B1 or B2) 12,000Btu/hr Capacity - Cooling - 2unit(A+B1 or B2) 20,000Btu/hr Capacity - Heating - 2unit(A+B1 or B2) 23,000Btu/hr Capacity - Cooling - 3unit(A+B1+B2) 29,000Btu/hr Capacity - Heating - 3unit(A+B1+B2)

Lab Activities CO2 Heat pump

CO2 Refrigerant Advantages Not toxic, odorless, non flammable, non explosive GWP : 1 ODP : 0 High refrigerating capacity, low compression ratio Possible to weight lightening and low cost Disadvantages Low critical temp.(31 ℃), high operating pressure

Refrigerant properties For A/C & heat pump application

CO2 Heat Pump System P-h diagram for R134a and CO2

CO2 Heat Pump System

Heat pump for a hot water heater Fig. CO2 heat pump water heating cycle

Heat Pump Instances DENSO

Heat Pump Instances HINOMARU CORPORATION SANYO DAIKIN MITSUBISHI

The Current State of Air-conditioning and Refrigerating Industry Figure: Worldwide air conditioner market conditions (’99) – 1million

The Characteristics of Air-conditioning and Refrigerating Industry Electron Medicine Environment control in semiconductor industry Clean room MRI Fiber Isothermal-isohumidity in fiber industry Air-conditioning and Refrigerating Industry Food Food storage Food processing Frozen storage Machine Architecture Heat treatment in metal industry Measuring device cooling installation Heating and cooling equipment for office Ventilating equipment equipment for Home Chemistry Freeze drying Refrigeration and liquefaction of chemical processes