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Client Projects - Case Study

Design of a Geothermal HVAC System for
G.W. Hewlett High School, Long Island, NY


  • Deteriorated heating plant approximately 50 years old serving the existing School facility of approximately 164,000 square feet in need of replacement. Hewlett High School
  • Protruding inefficient window air conditioning units utilized in limited areas of the Building. Hewlett High School
  • School programs and camps being held in uncomfortable environmental conditions during the summer months.
  • Inadequate outside air ventilation in classrooms.
  • Inadequate ventilation and lack of proper dehumidification for the pool facility.
  • Condensation and uncomfortable humid conditions experienced in the pool area.
  • Inadequate ventilation and strong chemical odor commonly experienced.


  • Dismantle the old deteriorated space consuming boiler plant, and install new renewable energy Geothermal Heat Pump Units with Energy Recovery Heat Wheels to provide complete individualized heating and cooling for the entire School complex.
  • Design a system for maximum reliability.
  • Design a system with long-term energy efficiency.
  • The majority of the new heating and cooling plant consists of heat pump units concealed within the corridor ceiling plenums. No unsightly protruding window air conditioners or large cooling towers generating noise and expelling large plumes of hot moist air are needed. No valuable space is lost.
  • The entire complex, both old and new, experience greatly improved air quality and maximum individualized climate control. Hewlett High School
  • Greatly reduces the operation and maintenance costs of thermal comfort.
  • Consumes less purchased energy than other types of HVAC systems, and ultimately reduces power plant emissions of greenhouse gasses into the atmosphere.
  • New state of the art Geothermal pool dehumidification system. Hewlett High School
  • Water side energy recovery is utilized to take advantage of otherwise wasted heat from the unit's condenser coil. The heat is absorbed and utilized as a preheat for the domestic water system.


  • Multiplicity of wells allows for Maximum redundancy of earth's heat exchanger. Required pumping energy is reduced by modulating the speed of the pump, based on pressure sensors monitoring the water control valves as they open and close at all the geothermal heat pump units. Hewlett High School
  • For much of the year, some of the geothermal heat pumps provide cooling, while at the same time others provide heating. This transfer of energy provides substantial energy savings.
  • The earth is utilized as heat exchanger by closed water loops into the ground, taking advantage of the earth's natural capacity for thermal storage.
  • System utilizes the earth as a heat exchanger, thus tapping the earth's energy for inexpensive, non polluting means of heating and cooling the facility, achieving the least environmental impact as compared to conventional systems.

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