Lecture Objectives Analysis of Absorption Cooling Cycles Absorption

Lecture Objectives: • Analysis of Absorption Cooling Cycles

Absorption cooling with preheater Rich ammonia vapor 4 5 Refrigeration and air conditioning (Ramesh et al)

Absorption cooling with preheater Saturated vapor at p 1’ 1’’’V=3 Major heat source 6 iso th er m 1’’’ 6 h 1’’’L =2 1’ 2’ , 2’’ Cooling tower 1 m g in ix 1’’ 4 5 Useful cooling energy Saturated liquid at p 1’ Saturated liquid at p 1 Pumping energy COP= Q cooling / Q heating (Pump ? ? ? )

hfg for H 2 O For Real energy analysis you need real h-x diagram! hfg for NH 3

Use of precooling (system improvement #2)

Absorption cooling with precooling Saturated vapor at p 1’ 1’’’V=3 Major heat source 6’ ix in 6 er m m 6 h g 1’’’ iso th Saturated liquid at p 1’ 1’’’L =2 Saturated liquid at p 1 Cooling tower 1’’ 1’ 4 4’ 2’ , 2’’ Useful cooling energy (larger!) 5 1 (needs to cool more!) Pumping energy

System improvement #3 Generator with Enrichment of NH 3 Different 8 V 9 8 L 10 8 LLP 11

Heat rejection with separation into liquid and vapor (Enrichment NH 3 in the vapor mixture) This is our point cooling Separator x 8 1 4=2 V 6=5 V Q 12 /m 1 m 8 5 rm m 1=m 2 2 is o th e mixture sub cooled liquid 7 8 Q 12 m 3 2 L x 1 x 8 cooling Q 45 /m 4

Ammonia Enrichment Process (rectification)

Absorption system with Enrichment (no preheater nor precooler) Saturated vapor at p 2 3 V 8 V ng xi mi 3 8 L 8 LLP 11 1’ 10 2 3 L Saturated liquid at p 2 1 9 Saturated liquid at p 1 Useful cooling energy

Example of H 2 O-NH 3 System • Text Book (Thermal Environmental Engineering) Example 5. 5 • HW 4: • Solve the problem 5. 6 from the textbook • Beside example 5. 5, you will need to study example 5. 6 and 5. 7

Li. Br-H 2 O Systems

Twine vessel Li. Br-H 2 O Systems

Useful information about Li. Br absorption chiller • http: //www. cibse. org/content/documents/Groups/CHP/Datashe et%207%20 -%20 Absorption%20 Cooling. pdf Practical Tips for Implementation of absorption chillers • Identify and resolve any pre-existing problems with a cooling system, heat rejection system, water treatment etc, before installing an absorption chiller, or it may be unfairly blamed. • Select an absorption chiller for full load operation (by the incorporation of thermal stores if necessary) as COP will drop by up to 33% at part-load. • Consider VSD control of absorbent pump to improve the COP at low load. • Consider access and floor-loading (typical 2 MW Double-effect steam chiller 12. 5 tons empty, 16. 7 tones operating). • Ensure ambient of temperature of at least 5°C in chiller room to prevent crystallization. • http: //www. climatewell. com/index. html#/applications/solar-cooling

System with no pump (Platen-Munter system) • H 2 O-NH 3 + hydrogen http: //www. youtube. com/watch? v=34 K 61 ECb. GD 4