Vapour Absorption Refrigeration Working Principle of Vapour Absorption
Vapour Absorption Refrigeration Working Principle of Vapour Absorption Refrigeration 1
2
3
4
5
Vapour Absorption & Vapour Compression Refrigeration 6
Basic Vapour Absorption System 7
Analysis of Vapour Absorption System 8
Example In an absorption system using Li. Br, TG=100 o. C, TE=10 o. C, Ta=30 o. C, Tc=40 o. C. Estimate the values of COP for the following conditions: 1. Ideal/Carnot cycle 2. A real cycle if pump delivers 0. 6 kg/s solution 3. If a heat exchanger is inserted after the pump and water enters the generator at 52 o. C. 4. If condensing temperature is reduced to 34 o. C, is there any chance of crystallization? 9
10
11
12
13
14
Aqua-Ammonia Absorption System 15
Aqua-ammonia vs. Li. Br System 1. Two systems have comparable COPs. 2. Aqua-ammonia system can provide temperatures below 0 o. C, but commercial Li. Br systems are limited to temperatures higher than 3 o. C. 3. Auqa-ammonia system requires extra components such as rectifier & analyser. 4. Aaqua-ammonia system operates at pressures higher than atmospheric, Li. Br systems operate at very low pressures. 5. Li. Br is very corrosive, hence require special inhibitors. 16
Problems with Vapour Absorption System 1. High initial cost 2. Shorter life (15 yrs for VA systems, 25 yrs for VC systems. ) 3. Requires more space 4. Requires more condenser water ( 4. 4 gpm/ton for VA systems, 3. 0 gpm/ton for VC systems), high capacity cooling tower and water treatment plant. 5. Requires chimney. 6. Require proper maintenance and longer downtime for overhauling. 17
- Slides: 17