Download Our design for the heating and cooling system is centered upon two

4.42J Design Proposal for the Sloan School of Management
Alexander Popov
Caroline Tien
I.
Introduction
This proposal for a new home for the Sloan School of Management aims to create a
facility that is efficient and whose innovative energy operation system is apparent from the
exterior. The building will consist of planned out floors that are dependent on the function of
the space. The facilities for heating and cooling will be located on top of and beneath the
building, with the upper facilities carefully integrated into the aesthetic design of the building.
We also plan to use the more efficient desiccant wheel, over the more traditional method of
cooling and reheating, for the dehumidification system.
II.
Heating and Cooling
Our design for the heating and cooling system is centered upon two energy storage
facilities located on top of the building and underneath it. The storage facilities will be used
for all of the cooling and partly for heating. The heating will be achieved by using a heat
pump, integrated into the energy storage facility. To achieve best performance, the building
will be well insulated, energy-efficient windows will be used and during the warmer months
night cooling will be implemented. To save energy sensors will be installed in the rooms, so
that they are conditioned only when someone is using them. A sensor measuring CO2 level
will be used to make sure proper ventilation is achieved. At a later phase a photovoltaic
system may be build on top of the upper energy storage facility to make use of the solar
energy and help cover the need for electricity. Detailed description of the heating and cooling
system follows in the next few paragraphs.
The building is divided into two areas for the purposes of the heating and cooling
(diag.1). The first area includes the dining facility and IT rooms, located on the ground floor
and the underground parking and auditorium. All of these need special air-conditioning as
compared to the rest of the building, that’s why they use a separate heating and cooling
system. The dining facility and IT rooms will need mainly cooling during the entire year
because of the energy released by the equipment used inside these spaces and the larger
number of people using them. The dining facility also requires better ventilation because of
the smells associated with cooking. As a result its air should not be reused but rather taken out
of the building. The IT rooms require lower humidity levels and will use a separate
dehumidification facility. The parking will not be heated or cooled and the auditorium needs
conditioning less frequently than the other rooms in the building because it will not be used so
often.
The second heating and cooling area includes the classrooms, study spaces, offices and
other spaces located on the upper floors. Since the classrooms and office spaces will be used
mainly between 8am and 6pm, only during this period they will be constantly conditioned.
After those hours, as well as during all times in the other rooms, conditioning will be provided
only when someone is present in the room. This will significantly reduce the operating time of
the heating and cooling systems.
The main advantage of using energy storage facilities is that they electricity can be
used mainly at night, when the rates are lower and also make a good use of the lower
temperature at night and in the cold months. The energy storage facilities in our case consist
of a well insulated tank full of cold fluid and three pipes going through in a way that will
insure good heat transfer between the pipes and the fluid (diag.2). The fluid will be water or if
cost permits, a fluid that has a lower freezing point and higher specific heat coefficient. The
functions of the three pipes are as follow. One pipe will act as the evaporator of the heat pump
that will be used for heating the building. Another pipe will be used to move outside air
through the tank, to lower the temperature of the water in the winter or at night (diag.3). The
last pipe will carry air from the building that needs cooling. The energy storage system on top
of the building will also have a smaller tank with warm water that will be used in the summer
to provide heating in the morning after the night cooling has ended.
We will look in detail only at the upper heating and cooling system because it’s a little
more complicated and the lower system functions in basically the same way. In each room
there will be three pipes coming within the same duct and one pipe leaving that will carry out
the exhaust air. The three pipes will bring respectively cold, warm, and outside air when
needed. The cold air will come at the lower comfort temperature for the time of the year and
the warm air will come at the higher comfort temperature. Depending on the temperature
inside the room, the right pipe will be opened until the temperature gets to the middle of the
comfort zone. The outside air pipe will be opened when CO2 level gets very high. On top of
the building there will be a control station that will make sure there is enough air flow in the
three pipes, that the air has the specified temperature, and that it has the right humidity (look
at the section about humidity for more information about this system). On diag.4 you can see
how the pipes come together and how the air moves. On diag.5 you can see the same
information for the lower energy storage system.
During the night there will be night cooling. Outside air will come in through the pipe
specified in the previous paragraph to cool the building. During the winter there will be only
an hour long cooling for better air quality in the building.
III.
Dehumidification
Controlling humidity is essential for protecting building components, optimizing
productivity by maintaining an optimal comfort level, preserving human health, and
minimizing mold growth. Traditionally, to control excess humidity in a building, companies
employ a cooling system that cools the air in order to reduce its ability to retain moisture and
then reheat it again to obtain a desired comfort level. However, this is not a very cost or
energy efficient process. In addition, many buildings must be maintained at a very low
temperature in order for this system to work.
There is now a way of using desiccants to produce a better, more efficient way to
dehumidify a building. Many recent studies have shown that it is a very effective moisture
control technique that also maintains low electric levels.
In this process, humid air is passed through a wheel, releasing its moisture to the
desiccant (i.e. silica gel, titanium gel, natural zeolites). Because the moisture extraction is an
exothermic process, the leaving air is usually cooled upon exiting the wheel, either by a heat
exchanger or cooling coils. However, unlike in traditional dehumidifying processes, the
cooling coils need only to cool the air instead of being responsible for dehumidifying as well.
Because the wheel operates independently of the cooling coils, humidity is independent of
temperature. Thus, the building can be maintained at a higher, more comfortable temperature
than if it was using the traditional cooling/reheating technique to dehumidify.
The desiccant wheel will become saturated as it adsorbs more moisture. At this point,
the wheel rotates slowly into the “reactivation air”. This is air that has been heated, and so, as
it passes through the wheel, it raises the wheel’s temperature, which moves the moisture in the
desiccant to the surface where it then enters the air stream. This moist air then leaves the
wheel and eventually the building.
While this process of dehumidifying seems like an excellent alternative to the
traditional method, it will be reviewed in more detailed in the weeks ahead to find a way to
best integrate it into the proposed building’s circulation design.
IV.
Final Remarks
Our proposed building is centered on the idea of an economically and environmentally
efficient operating system. The heating and cooling systems will be integrated into the
ultimate overall architectural design of the building. In addition, to provide an optimal
comfort level, a desiccant wheel will be used for dehumidification. While the building’s
design has not yet been finalized, we will continue to extensively build upon our initial
concepts and findings.