A cooling tower is delivering water to a chilled-water plant. The cooling tower outlet temperature has a 6°C approach temperature to the ambient air, wet-bulb temperature. The outside air conditions are 20°C dry bulb,
60% relative humidity. Using the psychrometric chart, at what temperature can the cooling tower deliver water to the chilled-water plant?

• A.21°C
• B.17°C
• C.13°C
• D.25°C

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You can buy air compressor A for $15,000 or air compressor B for $6,000. Compressor A will cost $10,000 per year to operate. Compressor B will cost $11,500 per year to operate. If both air compressors have a 10- year life and your required return on investment is 12%, which air compressor has the lowest total life-cycle cost?

• A.Compressor A
• B.Both air compressors have the same life-cycle cost
• C.Compressor B

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Which of the following statements regarding refrigerants is NOT correct?
5ELECT THE CORRECT ANSWER

• A.R-407C is a blended Hydro Fluoro Carbon or near Azeotropic mixture, and can be used as a replacement for R-22 in commercial applications
• B.R-11 and R-12 are Chloro Fluoro Carbons with significant ozone depleting potential
• C.R-1234yf is a Hydro Fluoro Olefin with zero ozone depleting potential, and little global warming potential
• D.R-22 is a Hydro Chloro Carbon with significant ozone depleting potential and significant global warming impact
• E.R-32 and R-134a are Hydro Fluoro Carbons with zero ozone depleting potential, and significant global warming impact

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What is a common cause of poor power quality?

• A.Synchronous motors
• B.Partially loaded induction motors
• C.Incandescent lighting
• D.Natural gas turbine power generation by utilities
• E.Electronic equipment, such as personal computers

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If the temperature difference across an external wall is 20°C and the heat flow across the wall is 2.5 Watts/m², calculate the insulation value of the wall (including inside and outside air films)?

• A.R = 8 m²-°C/W
• B.R = 10 m²-°C/W
• C.R = 12 m²-°C/W
• D.R = 6 m²-°C/W
• E.R = 4 m²-°C/W

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