Christiania Building - Sun Valley

At Issue

The Christiania Building presented a complex set of guidelines, restrictions, expectations and goals dictated by the community, the Owner/Developer, and the climatic conditions of the project location. The community was focused on preserving the existing charm and character of the town and minimizing both noise and environmental impact, within their already stringent design guidelines. The Owner's objectives were directed at providing the utmost functionality, flexibility, and ease of management for the dollar. The local climate, itself, posed further challenges, including an elevation of 6000', which reduces air density; daily temperature swings of 40 degrees F combined with an annual range of temperature from -15 degrees F to 93 degrees F; and annual snow accumulation of over 12'.

BGCE's Work

• Working with extreme equipment siting and space constraints, BGCE's design for all building systems encompassed 1800 square feet (four non-contiguous 400 SF rooms, and several 25-30 SF closet spaces on the upper floors), for a building that would typically require 3000-4000 SF for mechanical spaces alone.


• Geothermal heat pumps were located in the ceiling of tenant spaces to reduce drain on habitable square footage and provide for direct billing per the occupant's actual usage.


• To avoid noisy, expansive, and cost-prohibitive excavation required for the traditional condenser water loop typically buried 50'-300' below grade for heat rejected through the heat pumps, BGCE continued its system development by replacing the geothermal source with a time-proven cooling tower system in the parking garage, and added a boiler to input heat as needed by the condenser water loop.


• Modifying the system to utilize the snowmelt tubing as the primary channel for heat rejection, studies and calculations were conducted to theorize the eventual elimination and/or reduction in boilers and chiller tower equipment and sizing.


• To provide redundancy and maximize efficiency, multiple high-efficiency (90%) boilers and parallel pumping were staged.

Client Benefits

• The symbiotic exchange of heat throughout this system minimizes requirements of both boilers and cooling towers allowing elimination and/or reduction of equipment and sizing, translating into both significant first cost savings and life-cycle cost savings.


• Elimination and/or reduction in equipment sizing maximizes the square footage available for retail and for sale, increasing the Owner/Developer return on investment.


• Elimination and/or reduction in equipment sizing reduces the draw on natural resources and the use of fossil fuels.


• Connection of heat pumps to local tenants' separately metered electrical systems provides direct billing to tenants.


• Separate heat pumps provided in tenant spaces provide plug-and-play flexibility, i.e., if a tenant space expands or contracts the tenants can easily add or remove individual heat pumps.


• This hybrid system avoids all the drawbacks of deep excavation required of traditional geothermal heat pump condenser loops, including objectionable cost, noise, circulation, and visual impacts.


• Strategic configuration of the cooling tower in the garage allowed it to also provide garage exhaust as needed, eliminating the need for a separate fan system, again reducing first costs.


• Direct Digital Control (DDC) system provides automated monitoring and adjustment of system function, minimizing maintenance costs and maximizing system efficiency, and electronically reports potential problems and maintenance alerts to expedite resolution and minimize operational impacts.


• Snowmelted access roads, walkways, and balconies, provide safety and ease-of-access to users, an enhancement in the overall offering to retail, office, and residential occupants, alike.