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1. HVAC engineer
mechanical engineering question and need the explanation and answer to help me learn.
Requirements:
1/6 QuizInstructions20 ptsQuestion 1pConsider the case of moist air at Sea Level. Using the
ASHRAE Psychrometric chartfor English Units:
http://www.handsdownsoftware.com/ashrae-
chart.pdf(http://www.handsdownsoftware.com/ashrae-chart.pdf)Dry Bulb Temperature =
90 F, Dew Point = 80 F. Place this on the psychrometric chart, and determine (1) absolute
humidity (humidityratio), (2) Relative Humidity (%), (3) Wet Bulb Temperature (F), (4)
Enthalpy (BTU/lbmdry air), (5) Specific Volume (ft^3/lbm dry air).As an essay question,
you can paste the psychromentric chart in the answer with theanswers written on it. Or
place it in your work file.0 words>
2/620 ptsQuestion 2Consider a mixing process which occurs in the return duct of a
building. 20% outdoorair (100 F, 40% RH) is mixed with 80% return air from the zone (75
F, 50% RH). Mass FlowDry Bulb TemperatureRelative Humidity20%100 F40%80%75
F50%After mixing, the air moves toward the cooling coil. Please calculate the
followingproperties of the mixed flow:(1)Dry Bulb Temperature (F)(2)Enthalpy (BTU/lbm
dry air)(3)Humidity Ratio (lbm/lbm dry air)Place the humidity ratio in the answer to this
question, place the others in your work.Show the process on a Psychrometric Chart, label
(1) as the high temperature, (2) asthe low temperature, and (3) as the output state after
mixing.(note: you can loose points if w is correct, but temperature or enthalpy are wrong.)
10 ptsQuestion 3Consider the last problem. If the flow rates were given in volume flow
rather thanmass flow, what would the mixed value of the enthalpy be? (BTU/lbm dry air):
in otherwords, 20% volume flow at 100 F, 40% Rh and 80% volume flow at 75 F,, 50% RH.
3/65 ptsQuestion 40.0100.00450.022None of the aboveConvert a humidity ratio of 0.010
lbm H2O/lbm dry air into units of kg H2O/kg dry air.10 ptsQuestion 5A building is made up
of several zones an noted below. Using standard 62.1 asoutlined in the chapter (the current
standard may be slightly different), find theminimum total outside airflow needed in CFM.
ZoneCooling Flow Rate (CFM)# people expected in
zone160010240053800204300105500510 ptsQuestion 6Considering the PMV comfort
model. https://comfort.cbe.berkeley.edu/(https://comfort.cbe.berkeley.edu/)
4/6If a person is dressed in warm clothes (1.5 clo), and seated comfortably (1.0 MET), inan
environment of 63 F and 30% RH, 0 velocity, which is typical of my house inwinter, What is

2. the comfort level of the individual on the 7 point PMV scale (-3 to +3)?20 ptsQuestion
7What is the length of the day (sunrise to sunset) for Indianapolis on March 7th?(answer in
hours)Indianapolis Latitude: 39.7684 degrees NorthIndianapolis Longitude: 86.1581
degrees WestDay number: 66; number days per year: 3655 ptsQuestion 8TrueFalseSolar
Time for Indianapolis is the same as Eastern Standard Time.20 ptsQuestion 9Consider a flat
roof in Indianapolis on the summer solstice, where the declinationangle is a maximum at
23.45 degrees. Indianapolis Latitude: 39.7684 degrees North
5/6What is the angle of incidence of the sun on the flat roof at solar noon?20 ptsQuestion
10Consider the ASHRAE clear sky model of solar radiation for March 21st at 3:00 pmsolar
time for Indianapolis. (use the March 21st approximate values for the constantsin the
model)What is the direct beam component of radiation? (W/m^2 normal to the beam)20
ptsQuestion 11Consider the heat transfer through a standard double pane window on a cold
Marchday. The zone is kept at 20C, while the outdoor temperature is 7 C. The sky is
partlycloudy and the calculated solar radiation on the window is 500 W/m^2. What is
thetotal load on the zone caused by the 2 square meter window?(note + means heataddition
to the zone, - is a heat loss to the zone)Use U = 3.0 W/(m^2 C) for the double pane window
conductance.10 ptsQuestion 12Consider question 11 for a zone which has a net need for
heating on the cold Marchday. It is desired to lower the amount of heating needed. Would
this be better
6/6Quiz saved at 12:27amSingle Pane WindowTriple Pane WindowDouble Pane Low-e
Windowaccomplished by having a single pane window, a triple pane window, or a low-
edouble pane?30 ptsQuestion 13We will simulate the design conditions of a building in
winter with the outsidetemperature of -16.4 C (Indianapolis design), with a zone
temperature kept at 20 C.The building consists of 3 surface types:(1)Double Pane Windows:
U = 3.1 W/(m^2 C) (total window area 40 m^2)(2)Wall 6: U = 0.4 W/(m^2 C) (total wall
area 280 m^2)(3)roof 14: U = 0.31 W/(m^2 C) (total roof area: 300 m^2)(4)Ventilation for
21 people (10 l/s per person) (use Cp = 1.004 kJ/(kg K) and adensity of 1.2 kg/m^3)This a
10m x 30 m building x 4 m high. Draw the circuit diagram to calculate the heating load on
the space. (include in yourwork)Calculate the total heating load on the building at this
design condition. (in kW) (note:there is no ventilation to this building)Submit Quiz