One Pump Parallel Configuration
In one pump in parallel hmm configuration shown in Fig. 2.3 overall system performance and temperature conditions are shown in Table 2.2. In this configuration, there is the inherent problem. If both machines are operated in full-load range (15-100% of maximum capacity), and the overall response time of the system falls to 30% of the full load, each chiller will be functioning very effectively. Thus, most developers use the controls to mute one chiller when the overall system load, as evidenced by the return water temperature falls below 50% of full load.
However, with this pipeline arrangement if one cooler does not work, chilled water from operating hmm blend) with the return water passing through non-operating hmm, increase the cooling water inlet into the system. In many cases, it may not be a problem. But, as a rule, large internal spaces of buildings still require more or less complete cooling even at the perimeter of the space does not require cooling. Increased chilled water inlet may not satisfy these internal loads.
To try to fix the mixed water supply is a problem with one pump configuration, some designers have used hmm flow valves, as shown in Fig. 2.4. In this configuration, the flow through the non-operating hmm closed when the cooler is not working.
This mechanism leads to an increased flow from operating hmm, but not to reduce the mixing problem, as shown in Table 2.3...
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Chillers