◆ Vapour Compression Heat Pump that allows Performance Investigation from both Air and Water Sources.
◆ Rapid Stabilisation enables detailed Investigation in a Typical Laboratory Period
◆ Permits refrigerant pressure-enthalpy cycle diagrams to be drawn at all operating conditions
◆ Optional Computerised Data Acquisition Upgrade
◆ May be linked to Hilton Bench Top Cooling Tower H893 by addition of Reservoir System H060
◆ Optional RE590 Ground Source Simulator Available
◆ Two Year Warranty
Introduction
The vapour compression cycle is the most common form of refrigeration, transferring heat from the area being cooled to a higher temperature region. Heat Pumps use this effect to recover heat at a useful temperature for heating or some other process by upgrading low grade ‘free’ heat e.g. from ambient air or water.
Due to concerns about the effects of global warming, awareness of energy conservation must increase and heat pumps are an effective method of reducing energy consumption. Hence an understanding of their operation is relevant to many engineering disciplines.
The Hilton Air and Water Heat Pump R833 is a purpose designed and fully instrumented machine operating on ozone friendly R134a, which is not restricted under the terms of the Montreal Protocol.
The unit enables students to plot the pressure enthalpy and performance graphs as conditions are changed, so enhancing their understanding of the theory.
The unit will be a valuable teaching aid for students of:
● Refrigeration & Air Conditioning
● Building Services
● Mechanical Engineering
● Plant and Process Engineering
● Energy Conservation
● Energy Management
● Chemical Engineering
● Food Technology
● Marine Engineering
● Agriculture Engineering
Experimental Capabilities
The following experiments can be performed:
● Determination of Power Input, Heat Output and Coefficient of Performance.
● Production of Heat Pump Performance Curves over a range of source and delivery temperatures.
● Plotting of Vapour Compression Cycle on the Pressure Enthalpy diagram, and comparison with the Ideal Cycle.
● Energy Balances for the Components and the Whole Cycle.
● Estimation of Compressor Volumetric Efficiency Over a Range of Pressure Ratios.
● Estimation of Overall Heat Transfer Coefficients in the Evaporator and Condenser.
Description
R134a refrigerant vapour is compressed in an hermetic compressor and then flows to a water cooled condenser. Heat is transferred to cooling water and the refrigerant vapour is condensed to a high pressure liquid which passes through a thermostatic expansion valve.
A switch allows the user to direct the flow of the expanding vapour to either an air or water source evaporator where heat is extracted or the cycle is repeated. In order to recover waste heat from the compressor, the condenser cooling water also passes through a heat exchanger in the compressor casing. All components are mounted on a high quality ABS plastic panel and base.
Instrumentation includes pressure gauges, flowmeters, thermocouples and wattmeter allowing students to record all of the relevant parameters to create performance curves and refrigerant cycle diagrams.
The R833 incorporates mechanical fail safe over pressure cutout, together with a miniature circuit breaker and a 30mA residual current breaker for added protection.
Optional Data Acquisition Upgrade
An optional computerised data acquisition upgrade RC833A is available to enable all relevant system parameters to be automatically recorded on a PC for further analysis and display. Data may also be transferred to spreadsheet format for complex analysis and calculation. Refer to Page #6 for additional details.
Specification
A fully instrumented heat pump operating on the vapour compression cycle with a special heat pump hermetic compressor using R134a.
Three heat exchangers: air source finned tube evaporator, water source plate heat exchanger and water cooled plate condenser.
Controls:
Operating parameters may be varied by manual adjustment of the evaporator and condenser water control valves, and selecting the air or water source evaporator by panel mounted switch.
Instrumentation:
Gauges (2) for evaporating and condensing pressures
Multi-point Digital Temperature Indicator with 9 type K thermocouples. Resolution 0.1K
Flowmeters (3) for condenser cooling water and evaporator water flow rates and R134a flow rate.
Digital Wattmeter for compressor electrical energy.
All components are mounted on a high quality ABS plastic panel and base.
Safety Features: Condenser high pressure switch and compressor thermal overload switch. Residual current circuit breaker and a combined double pole main switch and overload cut out. All electrical components connected to common earth conductor.