che 350 problem set 8 when the ceiling surface temperature in the psu
ChE 350 Problem Set 8
When the ceiling surface temperature in the PSU Ice Pavilion drops below the dew point of the air in the
ice rink, water condensing on the ceiling will drip onto the ice surface, causing bumps to form. Your
assignment is to examine the effect of the emissivity of the ice rink ceiling on the propensity for
condensation; specifically, is it best to make the ceiling have a high or low emissivity? The ice rink can be
modeled as a large rectangular building with a 60 m x 20 m floor space and a 10.0 m high ceiling. You
may consider the ceiling to be a diffuse gray surface, the walls (all 4 of them) to be blackbodies at 10°C,
and the ice to be a blackbody maintained at -7°C. The air in the rink is maintained at 15°C with a relative
humidity of 70%. The convection heat transfer coefficient between the air and the ceiling, ice surface, and
walls is 5.0 W/m²K. The ceiling is separated from -5°C external air by a 0.30 m-thick layer of insulation
(-0.045 Wm ¹K¹), and the external convective resistance is negligible.
a. Draw a resistance network for a 3-surface enclosure that represents the radiation heat transfer between
the ceiling, ice, and side walls. Label the nodes and resistances, and calculate the value of each
resistance. The ice-ceiling view factor may be calculated using the result for aligned parallel rectangles
shown below. Other view factors can be determined using the summation and reciprocity rules.
b. Consider a flat ceiling with highly reflective panels (-0.05) or painted panels (-0.95). Calculate
the ceiling temperature in each case to determine if condensation would occur on the ceiling. The
dewpoint for the specified air temperature and relative humidity can be estimated using the Antoine
c. For each ceiling type, plot the ceiling temperature as a function of the insulation thickness (in the range
0.1-1.0 m) to identify conditions for which condensation would occur on the ceiling.
d. Plot the ceiling surface temperature as a function of the emissivity of the ceiling. What range of
emissivity values will prevent condensation on the ceiling? Should ice rink ceilings be designed with
high or low emissivity?
e. Plot the refrigeration load on the ice rink (i.e., the total rate of heat transfer to the ice) as a function of
the emissivity of the ceiling.
*The amount will be in form of wallet points that you can redeem to pay upto 10% of the price for any assignment. **Use of solution provided by us for unfair practice like cheating will result in action from our end which may include permanent termination of the defaulter’s account.Disclaimer:The website contains certain images which are not owned by the company/ website. Such images are used for indicative purposes only and is a third-party content. All credits go to its rightful owner including its copyright owner. It is also clarified that the use of any photograph on the website including the use of any photograph of any educational institute/ university is not intended to suggest any association, relationship, or sponsorship whatsoever between the company and the said educational institute/ university. Any such use is for representative purposes only and all intellectual property rights belong to the respective owners.