Energy Saving Tactics

Back in the mid-1990s we held a charrette to help a client comply with the parent company’s desire to be sustainable. We brainstormed all the ways that could contribute to that goal. Out of a list of 20+, we found that a few were surprisingly easy - recycling steel and drywall. We found a few were not legal or could not get approval in a reasonable timeframe, if at all - composting toilets, gray water re-use. We found that a geothermal system using an on-site pond was more energy-efficient than any other alternative. Through energy modeling we found out how valuable day-lighting was, and how the occupants’ connected load could undermine a lot of other goals. We set about implementing all the initiatives that were feasible; and especially concentrated on the three best tactics for saving energy - geothermal heating and cooling, day-lighting and reduced connected load.

GEOTHERMAL
HVAC is usually the main energy use in a building. Although a geothermal system has higher first costs, the energy consumed is reduced by mechanical advantage to the smallest amount for the same results. Often the first costs are paid back through reduced energy costs in three to ten years or less. Government subsidies (through 2016) figure into the calculation nowadays. We maxed out the pond capacity, and used a geothermal heat pump system for the 27,000 SF of offices. The extra pond capacity not needed for the offices was used in the plant for process heating.

DAY-LIGHTING
Artificial lighting is the second highest energy cost in commercial buildings. Day-lighting can reduce the use significantly, and has an additional bonus. Artificial lighting creates heat, which requires more air conditioning. So you save even more from day-lighting than just by not using lights. Energy use in commercial buildings over 10,000 SF is driven by what goes on inside rather than the envelope. House are the opposite. This has the curious result that commercial buildings are cooled nearly all year around. So the cooling savings from day-lighting is significant and not offset by a need for winter heating. This recent post on day-lighting is a roof monitor system used to light all new common spaces. Existing corridors were skylighted with frosted borrowed lights bringing the daylight into adjoining spaces. The pictures below show two day-lighting tactics that were used. Note the 'Sunbenders' to capture the maximum sunlight most of the year while providing some shading in summer months. Also visible are the PV panels used as window overhangs. The PVs powered the phone computer systems.

Roof Monitor - Interior

Day-light sources: Roof Monitors, Skylights

REDUCED CONNECTED LOAD
This is just a way of saying to use less power hungry devices. Some things to avoid: 

• Lighting unoccupied spaces - turn off the lights when you leave for even five minutes, get a sensor, turn on just what’s needed. We made extensive use of occupancy sensors.
• Space heaters - put on a sweater!
• Coffee makers that are on all day - get a pump thermos.
• Miscellaneous Gadgets - do without; if you can’t live without it see if there isn’t a USB version.
  

SUMMARY
All three of these initiatives have a payback, and make a building more valuable in an enduring way that bicycle racks and public transport access do not (but, that's a rant for another day). Your client will love you for minimizing his/her carbon footprint and cost of operation, whether you try for LEED certification or not. 
Epilogue
The building we designed passed to a new owner when our client’s business was purchased. Alas, the new owner wasn't interested in the building’s ’Green Pedigree’.