MODELLING AND SIMULATION OF ABSORPTION SOLAR AIR CONDITIONING SYSTEM

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MODELLING AND SIMULATION OF ABSORPTION SOLAR AIR
CONDITIONING SYSTEM

• Teclemariam Nemariam
• Department of Technology,
• Royal Institiute of Technology,
• Stockholm, Sweden
• email nemariam_at_egi.kth.se

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Aim

• To obtain best system performance of a solar
  assisted absorption cooling system
• Solar fraction
• Overall system efficiency
• Total cost
• Initial cost
• Maintenance cost
• Operational cost

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Methodology

• TRNSYS simulation program
• Transient Systems Simulation Program
• EES
• Engineering Equation Solver

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System Description

• Energy source Refrigeration Load
• cycle

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System Description

• Solar collector
• Thermal storage tank
• Auxiliary heater
• Absorption refrigeration chiller with cooling
  tower
• Building
• Diverter
• Tee-piece
• Relief valve
• Piping system

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Trnsys Block Diagram
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Absorption Refrigeration System
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Absorption Refrigeration System

• Refrigerant
• water
• Absorbent
• Lithium bromide

• Stages
• Single-effect
• G. temp 80 100 C
• COP 0.6 0.8
• Double-effect
• Gen. Temp 100 160 C
• COP 1.0 1.2
• Triple-effect
• Gen. Temp 160 240 C
• COP ABOUT 1.7

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Absorption Refrigeration System
Poor refrigerant
Strong refrigerant
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Absorption Refrigeration System

• Drawbacks
• Water
• Temperature greater than zero
• High water vapour pressure
• Large volume
• Lithium bromide
• Precipitate at low temperature

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Building

• Details of a building are
• Location latitude, longitude, altitude
• Type Office, recidential, hospital,...
• Size volume, area of walls, roof, floor,
  windows, door, ..etc
• Types of construction materials
• Outside design conditions
• Inside design conditions
• Internal gains

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Work done so far

• More than 75 course work
• More than 80 literature survey
• Modelling and simulation of a complete system
  using standard TRNSYS components

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Sample Simulation Results

• Solar collectors
• Evacuated collector, high quality flat plate
  collector and ordinary flat plate colector
• Storage tank cylinderical, vertical stand
• Heater gas fired
• Single-effect absorption machine
• Refrigerant water and absorbent lithium bromide
• Capacity 24.44 kW

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Sample Simulation Results

• Building
• Location Assab, Eritrea. Latitude 13.07 N,
  longitude 42.6 E, altitude sea level
• Type two storey office
• Size volume, area of walls, roof, floor,
  windows, door, ..etc are given in detail
• Types of construction materials
• Outside design conditions
• Inside design conditions
• Internal gains
• Every detail is given

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Sample Simulation Results

• System Optimization
• e.g. collector slope

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Sample Simulation ResultsSolar fraction as a
function of colector area and storage volumee.g.
using evacuated collector
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Sample Simulation Results

• System efficiency as a function of colector area
  and storage volume
• e.g. using evacuated collector

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Sample Simulation Results

• Solar fraction and system efficiency as function
  of collector area for a given storage volume

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Sample Simulation Results

• Yearly insolation energy, max possible solar heat
  gain and cooling load

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Notice

• The sample simulation result is extracted from a
  paper presented in the ISES Conference June 14-19
  2003 in Götemberg, Sweden.
• If you have more interest please refer the paper.
• Thank you.