According to the U.S. Green Building Council, buildings account for 72 percent of electricity consumption. The Nature Center relies on an integrated design of heating and cooling systems and controls to ensure the most efficient and sustainable use of energy. Efficient heating, ventilation and air-conditioning (HVAC) reduce the amount of energy used throughout the building.
In-floor Radiant or Hydronic Heating:
Fluid heated in the solar thermal system is pumped through a system of tubes that run throughout the building’s concrete flooring, heating each room from the ground up.
Two-stage variable speed 95%+ efficient furnaces and 20 SEER air conditioning units make up the major HVAC equipment. These units were selected in conjunction with Madison Gas and Electric’s engineering department to provide a highly efficient system, at an economical cost.
Heat generated by people and computer equipment can require cooling to keep the indoor air temperature comfortable. When the outdoor air allows (typically in the spring and fall months), the economizers will utilize the ambient air in lieu of running the air conditioning equipment, thus saving electricity.
All air exhausted from the main restrooms pass through an air-exchanger that reclaims heat and transfers it to the fresh air brought in from the outside. For example, during the cold winter months, the indoor air temperature is approximately 68 degrees, where the ambient air temperature could be zero. Energy in the form of heat is reclaimed from the exhaust to pre-heat the fresh outdoor air.
HVAC System Controls:
An integrated HVAC system will automatically control the use of radiant in-floor heating or air conditioning as needed, so that each system operates at maximum efficiency. The controls system will also account for changes in the need for heating and cooling. For example, in the cool spring and fall days, the building could require heat in the mornings and cooling in the afternoons. The control system will limit overshooting the heat requirement, preventing excess cooling later in the day.
Cooling in the new facility is provided by two zoned high-efficiency air cooled condensing TRANE systems. The cooling unit for the original building has been replaced with a more efficient unit.
The heat generated by computers and electronic devices will be circulated for use in other parts of the building during the heating months.
In addition to their role in providing natural daylight for workspaces, windows are used to control heat and cooling. Windows along the south-facing wall of the exhibit area are electronically-controlled to automatically open and close depending upon the heating/cooling need. The amount of glass on the north side of the building is minimized to control heat loss.
The roof membrane on the addition is a white membrane, donated by ABC Supply that reflects sunlight instead of absorbing it as a black roof would. This reduces the cooling load during the summer months.