please answer with an understandable simple handwriting..... 1. True or false: h

Question

please answer with an understandable simple handwriting.....

1.      True or false: heating air de-humidifies it.

2.      What capacity (power) electric heater would be needed to raise the temperature of 300 cubic feet of concrete from 65° F to 150° F in 120 minutes? As this is electrical power, state response in watts or kilowatts.

3.      What would be the total cost of #2 fuel oil to operate a boiler expected to perform the task in question 2 if the boiler were operating at full fire with an efficiency of 80% and the cost of #2 fuel oil is $2.50/gallon?

4.      How does a chilled beam save energy in the operation of an HVAC system?

5.      What are the four major components of a vapor-compression refrigeration machine?

6.      What is the purpose of a VFD in an HVAC system?

7.      What is the typical, rule of thumb, supply air temperature to a space in

a.       Heating mode?

b.      Cooling mode?

8.      What air flow rate would be required to maintain a space at 70 degrees F if it had a heat loss of 55,000 BTU/HR?

9.      What hot water flow rate would be needed to provide the heating needs identified in question 8 if the hot water supply temperature is 180 degrees F and the leaving water temperature is 160 degrees F?

10.  Refer to the attached pump/fan curve chart. Name the three “typical” curves that are shown. Which of these three curves is calculated by the design engineer? (It is not necessary to attach the curve chart to your response).

a.       Curve A is the   ______________________________curve.

b.      Curve B is the   ______________________________curve.

c.       Curve C is the _______________________________curve.

d.      Curve _____ is calculated by the design engineer.                 

11.  What are two of the purposes of an economizer section in an air handling unit?

12.  Which component of a vapor-compression refrigeration machine provides for the cooling effect in the conditioned space?

13.  How does a condensing boiler operate more efficiently than a conventional boiler?

14.  What is the primary purpose of a stair pressurization system?

15.  What are the three component steps in fire suppression?

16.  Why would one choose a fire tube boiler instead of a water tube boiler?

17.  How does one de-humidify an air mass?

18.  Define an HVAC zone?

19.  If deciding on replacing an existing, 80% efficient hot water boiler with a new 95% efficient condensing hot water boiler, what potential consequences should be considered? (I.E. why may installing a condensing boiler not be a good idea?)

20.  What does a VAV terminal box do?

Explanation / Answer

1. False , on heating moisture content remains same.

2.Initial temp. = 65°F =18.3333°C , Final temp. =150°F = 65.556°C , Q = 300 ft^3 =8.495m^3 , density = 2400kg/m^3

Specific heat = 1000j/kg , time = 120min. = 7200sec.

Power of heater = m*cp* (T2-T1)/ (time ) = 8.495*2400*1000*(65.556-18.333)/ (120*60) = 133.72 kW

3. No of gallons required = Total required energy/ Heating value/ efficiency = 133.72*1000*120*60/133000/ 1055/0.8 = 8.6 gallons

Hence , cost = no of gallons* cost of 1 gallons = 2. 5* 8.6 = $21.5

4.Excessive fan energy is minimized in chilled beam which saves energy.

5. Four major components are - compressor, condensor, throttling valve, and Evaporator.

6. Based on demand , VFD adjusts the speex of fan or pump motor ,hence saves energy and prolonges equipment life.

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