Jain & Associates has created the following energy conserving designs in the past:

Thermal storage systems using water, ice, chemicals and rocks
Heat recovery systems for air and water
All types of heat pump systems
Carbon Dioxide sensors for control of fresh air
Occupancy sensors for control of lighting and a/c systems
Variable Speed Air Handling and Water Circulation Systems
Water-conserving plumbing fixtures including waterless urinals, double-flush & composting toilets, etc.
Photocell control of interior and exterior lighting
Wind-power systems
Biomass energy systems