Near Zero Energy HVAC for Laboratories
K.P.S. Ramesh, Air Treatment Engineering Pvt. Ltd.
This presentation will address various designs of HVAC system that achieve near zero power.
The project design specifications are: 40,000 square feet total, with 10 laboratories of 4,000 square feet in each laboratory. The equipment load for each laboratory is 20 kilowatts after 70 percent diversity, there are no clean rooms or radioactive laboratories, and there are 150 variable air volume (VAV) fume hoods
This presentation will use ASHRAE data for global locations including:
- The United States: San Francisco and Chicago
- China: Beijing and Shanghai
- India: Mumbai and Hyderabad
- Saudi Arabia: Dhamam and Riyadh
Energy-saving techniques considered will include:
- Enthalpy recovery wheel with innovative design ensuring zero cross contamination (first time in the world; patent to be applied).
- Heat pipe as heat recovery and pipe materials suitable for harsh chemical exposure, but with equal efficiency as the metallic pipes (first time in the world; patent to be applied).
- Heat pipe as run-around coil with facility for RH control using controlled heating techniques.
- Plate-type heat exchanger for reheat and RH control with controllability of room RH.
- Non-metallic, chemically resistant heat exchanger for heat recovery and pre cooling of air.
- Multi-stage, indirect evaporative cooling to be used for heat recovery and also as a near replacement to refrigerant-based air conditioning (AC) systems.
- Hygroscopic shower/dew point bath as a cooling and air cleaning mechanism.
- Isothermic steam generator design (first time in the world; patent to be applied) and application of the same for RH management.
- Use of zone pumping and elimination of two-way control valve in the air handling units for better performance of coil.
- Use of refrigeration-based hazardous waste generator: addressing the problem of "no load syndrome."
- Dehumidification using dehumidification wheels operated on solar reheat, hence no conventional AC.
- Combination of more than one system above to achieve/eliminate conventional cooling techniques.
- Ducting design without balancing damper.
Power and TR harvesting:
- Based on the above, derive the total thermal and electrical power required on each of the eight conditions on a peak day.
- To ensure net zero energy, the following techniques can be used: solar AC; solar AC without battery storage; deep earth geothermal (new concept and the energy answer of the future), earth air tunnel; radiant cooling using slab, radiant panels, and chilled beams; and waste-to-energy, mostly from chemical wastes in production/city waste.
- District energy center for large users.
Conclusion:
Combinations of the above energy-saving techniques and power and TR harvesting derive the final energy demand, which in most of the eight cases will be near zero demand.
K.P.S. Ramesh is a mechanical engineer with 28 years of experience in HVAC and controls. Mr. Ramesh owns and runs a leading consulting company, Air Treatment Engineering Pvt. Ltd., and has been practicing as a consulting engineer for the past 20 years. Mr. Ramesh designed various critical laboratories with VAV systems and cleanrooms. Examples of the laboratory projects include United States pharmacopeia, Novartis, Lupin, Reliance Life Sciences, Alexandria, and SGS. Mr. Ramesh is a member of ASHRAE, the U.S. Green Building Council, the Indian Society of Heating Refrigerating and Air Conditioning, IPA, and the International Code Council. Mr. Ramesh has designed world-class green buildings of LEED® Platinum rating and very energy-efficient, near zero buildings. He has traveled throughout the world and has participated in various seminars.