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VARS based on Ammonia-Water Pair


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Refrigeration Systems

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VARS based on Ammonia-Water Pair

  1. 1. Vapor Absorption Refrigeration Systems Based On Ammonia-Water Pair
  2. 2. • Vapour absorption refrigeration system based on ammonia- water is one of the oldest refrigeration systems. • Ammonia is used as a refrigerant and water is used as an absorbent. • Lithium bromide systems operate under very low pressures, the ammonia-water system is operated at pressures much higher than atmospheric . • Ammonia is both toxic and flammable. Hence, these systems need safety precautions.
  3. 3. Vapor Absorption Refrigeration Systems Based On Ammonia-Water Pair
  4. 4. For Ammonia-Water pair Circulation ratio - Is the ratio of the mass of the weak solution to the refrigerant mass flowrate. λ=mws/m
  5. 5. Condenser m1= m2= m Qc=m(h1-h2) Expansion Valve m2=m3=m h2=h3 Evaporator m3=m4=m QE=m(h4-h3)
  6. 6. Absorber m + mss = mws QA=mh4+λh10-(1+λ)mh5 Pump m5=m6=mws Wp=mws(h6-h5) Wp=λm(h6-h5) Heat Exchanger m6=m7=mws m8=m9=mss
  7. 7. Generator m7=m8+m1 QG=mh1+λmh8-(1+λ)mh7 Expansion Valve m9=m10=mws h9=h10 COP=QE/(QG+Wp)
  8. 8. Comparison Between Compression and Absorption Refrigeration Systems