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A PROPERTY ENERGY SUCCESS STORY, RANCHEO MURIETA
- Partner Information
Located in Sacramento, CA
10,000 s.f. facility
Annual Cash Savings: $5800
Annual Energy Savings: 68,571 kWh
Prevented 82,423 pounds of pollution
Service and Product Provider
Sacramento Municipal Utility District (SMUD)
6301 S Street, MS A204
Sacramento, CA 95817
916-732-5438
http://www.smud.org 
The Rancho Murieta Association oversees a gated community with many
public buildings and large grounds. This includes buildings, lakes,
roads, parks and recreation areas, and a child care facility/preschool.
Greg Vorster, of the Rancho Murieta Association contacted Greg Miller,
energy specialist for the Sacramento Municipal Utility District (SMUD),
for assistance in stemming the Association's growing energy usage. The
Association had previously worked with SMUD to improve lighting efficiencies
in the public areas and pumping for the numerous fountains. When the
Association needed to take a look at the existing HVAC systems, they
again looked to SMUD for assistance.
There was a 31-ton chiller, which had been in place for over 30 years.
Zoning was clearly with this unit and proper heating and cooling levels
were no longer being maintained. Comfort levels for the varied uses,
such as the office, meeting room and childcare areas, were not being
met. There was no gas service available to these facilities and initial
review indicated a good application of heat pumps. Site analysis indicated
that granite bedrock would preclude the use of a deep well ground source
heat pump system and space precluded a horizontal loop system. It appeared
that air source units would be the only answer, but luckily there was
a lake owned by the Association nearby. After trenching 450 feet and
insulating refrigerant running lines, the four heat transfer exchange
coils were weighted to sink into the lake.
The total costs for the 8-15 SEER water source systems were only slightly
higher than for an air source system while the efficiency proved to
be considerably higher. Cooler water temperature contributes to a higher
efficiency system through greater opportunity for heat exchange. A replacement
chiller would have been significantly more expensive. The total expenditure
of the installation was $39,000. SMUD provided efficiency incentives
of $4,800 for savings of 32kW, 68,571 kWh and $5,800 annually. This
system will pay for itself in just under seven years.
The Association has found that comfort levels to all of the varied
zones were dramatically improved. Office staff no longer had to wear
sweaters to survive the cold from the chiller. Also, safety and reliability
were a big consideration in this improvement. Finally, the Association
members (residential property owners) were aware that this was a high
technology installation and were proud to have this as part of their
community.
However, there were several obstacles along the efficiency path that
were successfully overcome. Both the Association and residents raised
concerns regarding the effect on the fish of the temperature change
due to heating exchange coils being placed in the lake. Analysis showed
that the size of this system and the related heat exchange loops would
not change the temperature enough to have an effect on the fish population.
The Association has committed itself to future energy efficiency upgrades
and will continue to evaluate the available options and make sure to
see the big picture. While heat pumps were clearly the answer for this
facility, research into the most efficient technologies and being open
to a creative approach has given them an installation to be proud of.
Please click on link to view original article:
http://www.energystar.gov/index.cfm?c=sb_success.sb_successstories_rancho
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