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Emerson
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Emerson Climate Technologies Digital Scroll technology is rooted in a simple yet effective method of capacity modulation. This new technology enables the Digital Scroll to outperform various existing modulation technologies in terms of efficiency, reliability, performance, and exceptional comfort cooling, which only proves that Digital Scroll technology is the best in its class. |
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Digital Scroll Technology
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Compressor capacity can be changed by varying the relative amount of time in the loaded and unloaded states, which are changed by opening or closing the PWM valve. Capacity is time averaged summation of loaded and unloaded states, and its range is continuous from 10%-100%. Regardless of capacity, the compressor always rotates with constant speed. |
| Inverter Technology |
Compressor capacity can be changed via the inverter control circuit. Capacity is changed by changing the motor frequency and, hence, compressor speed. The modulation capacity range is in steps, from 47%-130% (frequency ranges from 30-100Hz). The system can run at high frequencies for only short period of time since this increases both oil circulation rate and the motor temperature. |
| Multiple-Step Compressor |
Compressor capacity can be changes via the hot gas bypass circuit. Capacity is changed by opening or closing bypass solenoid valves of a power control compressor. For a 2-number twin rotary compressor, the modulation capcity range is only 8-step. |
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Digital Scroll Technology
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Excellent. No inverter loss and low power consumption in the unloaded state (only 10% of full load power) mean low average power consumption and high partial load efficiency. |
| Inverter Technology |
Average. Inverter loss accounts for approximately 15% of total power consumption. Inefficient hot gas bypass method must be used for low capacities. Liquid injection must be used under conditions of high ambient temperature. |
| Multiple-Step Compressor |
Good only at 50% and 100%, where modulation doen't require hot gas bypass. Poor in the steps where hot gas bypass must be used. |
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Digital Scroll Technology
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High. There is no inverter loss and hot gas bypass is never needed, thus, saving energy throughout the year. |
| Inverter Technology |
Average, because inverter loss always occurs and hot gas bypass must be used at low capacities. |
| Multiple-Step Compressor |
Low, because hot gas bypass must frequently be used. |
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Digital Scroll Technology
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Precise. Continuous and step-less capacity modulation is achieved throughout the operation range allowing a faster response to low requirement changes. |
| Inverter Technology |
Average. Room temperature stabilizes near the set temperature after a long warm-up period. Multi-step increase in respond to load requirements changes causes unstable room temperature during the transition period. |
| Multiple-Step Compressor |
Not Precise. Room temperature control cannot be stable since it only has a few steps for capacity modulation. |
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Digital Scroll Technology
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During each cycle, the compressor will be in fully loaded state for a few seconds. The high mass flow during the state results in a lower evaporating temperature and, hence, effective dehumidification. |
| Inverter Technology |
The speed of inverter compressor and the velocity of gas return will be both very slow, which increase the evaporating pressure and temperature resulting in weak dehumifying capacity. |
| Multiple-Step Compressor |
A lot of discharged gas must be bypassed and the velocity of gas return is very low. This causes higher evaporating pressure and temperature, resulting in weak dehumidifying capacity. |
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Digital Scroll Technology
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High reliability and running life. Simple PCB and pipe circuitry of the outdoor mean high reliability. Furthermore, Digital Scroll has been designed to have a running life of 15 years. |
| Inverter Technology |
Low Reliability. Intricate PCB and pipe circuitry for the outdoor unit, complicated electronic controllers in the system, and mechanical complexity translate to low reliability. |
| Multiple-Step Compressor |
Short running life. Not only is a rotary compresor less efficient than a Scroll compressor, but the blade of the rotary twin compressor also easily wears out. |
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Digital Scroll Technology
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Complies with EMC requirements. |
| Inverter Technology |
Electromagnetic Suppression Electronics are required to comply with EMC requirements. Generates problematic high-frequency harmonic waves. |
| Multiple-Step Compressor |
Complies with EMC requirements. |
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According to the ARI 210/240 standard, the COP on 4 points (25%, 50%, 75%, 100%) are required for calculating the IPLV (or SEER). |
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e.g. Because more indoor units from the same refrigerant system are turned on. |
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