A reoccurring theme is Sheldon Cooper’s spot on the sofa,
which nobody else is allowed to occupy. When questioned why, he states that “In
the winter that seat is close enough to the radiator to remain warm and yet not
so close as to cause perspiration. In the summer it’s directly in the path of a
cross breeze created by opening windows”.
But what if the science is wrong and this is not the optimum
position in the room?
HVAC Flow Simulation Model, we can find out.
Initially a simplified CAD model of the apartment was
constructed, keeping the key geometry as accurate as possible.
To fully determine the optimum position for both winter and
summer seasons, two studies will have to be run. The following presumptions had
to be made:
Additional parameters include a draft of 0.001m3/s
draft under the door, Environmental Pressure to simulate an accurate window
opening and Static Pressures on the bedroom doors.
Below is a plan view of the apartment, showing all heat
sources and conditions.
The two different studies were run, totalling a combine
solve time of 4 hours.
Below are image of the two studies, showing a temperature
cut plot and flow trajectory from the draft under the front door. Notice the
air flow across Sheldon’s spot:
At this point, we can establish exactly where Sheldon should
sit to experience the optimum comfort. This will be utilising SOLIDWORKS Heating Ventilation & Air
Conditioning (HVAC) module.
The plot that we will be using to evaluate the study will be
the Predictive Mean Vote (PMV). The PMV
was developed by Povl Ole Fanger at
Kansas State University as an empirical fit to the human sensation
of thermal comfort and has been adopted by the ISO standards.
It predicts the mean
response from a large group of people on a seven-point thermal scale between -3
and +3. Below is an annotated scale:
- +2 warm
- +1 slightly warm
- 0 neutral
- -1 slightly cool
- -2 cool
- -3 cold
Comparing the above PMV plots, we can see that seat X would actually
be suitable for Sheldon to sit on. It scores a score of zero, for both the
winter and summer plots.
We could further look into the problem and actually suggest
an alternative room layout to provide an optimised seating position. As there
is a greater degree of fluctuation in the summer plot, we shall use this as our
basis. Repositioning the sofa, moving it slightly forward would provide a
better comfort level (pictured below). Any alterations however would most
definitely have to be put through the Roommate