A small building houses 150 people, various machines and computers and maintains the inside air temperature at constant 20 C.  The temperature of the surroundings is a constant (-5C) which causes a heat loss from the building.  The heat loss can be treated as a convective heat loss with a (hA) product of 563 W/K.   The heat input from each person is 178 W and from the Machines and computers it is 75000 W. These operating conditions apply for an 8 hour period.  There is sufficient air mass in the system to provide oxygen to the people.  

• Determine if the building requires an air conditioning unit (Remove energy from the building) or a furnace (Provide energy to the building) using an energy balance for the 12 hour period to maintain the above conditions.
• What is the magnitude of the heat flow (J) for the device you identified in part “a”?