HVAC & Plant Utilities interview questions

1. A.kW per ton of refrigeration, about 0.6 for a centrifugal and 0.8–1.0 for a screw chiller, the key efficiency figure of a plant
2. B.1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity
3. C.fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
4. D.kW per 100 cfm delivered, around 18–20 for a good screw compressor, with leaks often wasting 20–30% of generation

Answer + AI explanation with Pro

1. A.Steam trap
2. B.Chiller specific power
3. C.Cooling tower approach
4. D.Cycles of concentration

Answer + AI explanation with Pro

1. A.Chiller specific power — kW per ton of refrigeration, about 0.6 for a centrifugal and 0.8–1.0 for a screw chiller, the key efficiency figure of a plant
2. B.Chiller specific power — difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop
3. C.Chiller specific power — preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers
4. D.Chiller specific power — 1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity

Answer + AI explanation with Pro

1. A.direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses
2. B.valve that discharges condensate while holding steam, in thermodynamic, float or thermostatic types, with failed-open traps a major steam loss
3. C.ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
4. D.difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop

Answer + AI explanation with Pro

1. A.Chiller specific power
2. B.Steam trap
3. C.Cooling tower approach
4. D.Cycles of concentration

Answer + AI explanation with Pro

1. A.Cooling tower approach — 1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity
2. B.Cooling tower approach — direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses
3. C.Cooling tower approach — preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers
4. D.Cooling tower approach — difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop

Answer + AI explanation with Pro

1. A.ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
2. B.kW per ton of refrigeration, about 0.6 for a centrifugal and 0.8–1.0 for a screw chiller, the key efficiency figure of a plant
3. C.fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
4. D.1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity

Answer + AI explanation with Pro

1. A.Indian Boiler Regulations
2. B.Variable frequency drive savings
3. C.Compressed air specific power
4. D.Energy audit

Answer + AI explanation with Pro

1. A.Indian Boiler Regulations — fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
2. B.Indian Boiler Regulations — kW per 100 cfm delivered, around 18–20 for a good screw compressor, with leaks often wasting 20–30% of generation
3. C.Indian Boiler Regulations — preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers
4. D.Indian Boiler Regulations — 1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity

Answer + AI explanation with Pro

1. A.ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
2. B.fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
3. C.kW per 100 cfm delivered, around 18–20 for a good screw compressor, with leaks often wasting 20–30% of generation
4. D.direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses

Answer + AI explanation with Pro

1. A.Cooling tower approach
2. B.Cycles of concentration
3. C.Indian Boiler Regulations
4. D.Boiler efficiency methods

Answer + AI explanation with Pro

1. A.Boiler efficiency methods — ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
2. B.Boiler efficiency methods — preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers
3. C.Boiler efficiency methods — 1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity
4. D.Boiler efficiency methods — direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses

Answer + AI explanation with Pro

1. A.preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers
2. B.difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop
3. C.direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses
4. D.kW per 100 cfm delivered, around 18–20 for a good screw compressor, with leaks often wasting 20–30% of generation

Answer + AI explanation with Pro

1. A.Chiller specific power
2. B.Cooling tower approach
3. C.Indian Boiler Regulations
4. D.Compressed air specific power

Answer + AI explanation with Pro

1. A.Compressed air specific power — kW per 100 cfm delivered, around 18–20 for a good screw compressor, with leaks often wasting 20–30% of generation
2. B.Compressed air specific power — ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
3. C.Compressed air specific power — difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop
4. D.Compressed air specific power — fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half

Answer + AI explanation with Pro

1. A.1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity
2. B.direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses
3. C.ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
4. D.difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop

Answer + AI explanation with Pro

1. A.Indian Boiler Regulations
2. B.Cooling tower approach
3. C.Chiller specific power
4. D.Cycles of concentration

Answer + AI explanation with Pro

1. A.Cycles of concentration — valve that discharges condensate while holding steam, in thermodynamic, float or thermostatic types, with failed-open traps a major steam loss
2. B.Cycles of concentration — kW per ton of refrigeration, about 0.6 for a centrifugal and 0.8–1.0 for a screw chiller, the key efficiency figure of a plant
3. C.Cycles of concentration — ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
4. D.Cycles of concentration — direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses

Answer + AI explanation with Pro

1. A.direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses
2. B.difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop
3. C.ratio of dissolved solids in cooling water to that in make-up water, run at 3–5 to save water without scaling
4. D.preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers

Answer + AI explanation with Pro

1. A.Cooling tower approach
2. B.Indian Boiler Regulations
3. C.Compressed air specific power
4. D.Energy audit

Answer + AI explanation with Pro

1. A.Energy audit — direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses
2. B.Energy audit — fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
3. C.Energy audit — valve that discharges condensate while holding steam, in thermodynamic, float or thermostatic types, with failed-open traps a major steam loss
4. D.Energy audit — preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers

Answer + AI explanation with Pro

1. A.1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity
2. B.fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
3. C.preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers
4. D.kW per 100 cfm delivered, around 18–20 for a good screw compressor, with leaks often wasting 20–30% of generation

Answer + AI explanation with Pro

1. A.Cycles of concentration
2. B.Boiler efficiency methods
3. C.Indian Boiler Regulations
4. D.Variable frequency drive savings

Answer + AI explanation with Pro

1. A.Variable frequency drive savings — kW per 100 cfm delivered, around 18–20 for a good screw compressor, with leaks often wasting 20–30% of generation
2. B.Variable frequency drive savings — fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
3. C.Variable frequency drive savings — 1950 rules under the Boilers Act 1923 requiring approved design, certified welders and annual inspection for any boiler above 22.75 litres capacity
4. D.Variable frequency drive savings — valve that discharges condensate while holding steam, in thermodynamic, float or thermostatic types, with failed-open traps a major steam loss

Answer + AI explanation with Pro

1. A.valve that discharges condensate while holding steam, in thermodynamic, float or thermostatic types, with failed-open traps a major steam loss
2. B.difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop
3. C.direct method compares steam output with fuel input, while the indirect method of IS 8753 sums stack, radiation and unburnt losses
4. D.fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half

Answer + AI explanation with Pro

1. A.Boiler efficiency methods
2. B.Steam trap
3. C.Compressed air specific power
4. D.Cooling tower approach

Answer + AI explanation with Pro

1. A.Steam trap — preliminary walk-through or detailed instrumented study under the Energy Conservation Act 2001, mandatory for designated consumers
2. B.Steam trap — difference between outlet cold-water temperature and ambient wet-bulb, typically 3–5 °C, while range is the inlet-to-outlet water drop
3. C.Steam trap — fan and pump power falls with the cube of speed under the affinity laws, so a 20% speed reduction cuts power by about half
4. D.Steam trap — valve that discharges condensate while holding steam, in thermodynamic, float or thermostatic types, with failed-open traps a major steam loss

Answer + AI explanation with Pro