Performance Comparison

Figure 38-27 compares conventional absorption machines including single-effect (1E) NH3 and LiBr and double-effect (2E) LiBr machines, as well as developing GAX machines, including the basic GAX-cycle system and the VX and Branched (B) GAX-cycle systems. The assumed condenser temperature is 91°F (33°C) and lifts range from 126 to 18°F (70 to 10°C), corresponding to evaporator temperatures of between -40 and 41°F (-40 to 5°C). The following characteristics are evident in the figure: • The COP of the conventional single-effect NH3

machines remains fairly constant over the full range, indicating superior performance under high-lift conditions and relatively poor performance under low-lift conditions.

• NH3 cycles can operate at very low evaporator temperatures, while the LiBr machines are limited to the higher temperature range.

• Very high prospective COPs are indicated for advanced GAX cycles, particularly as cycle lift is decreased. The VX GAX-cycle systems show the best COP under high-lift conditions, indicating attractiveness for industrial refrigeration applications.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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