Hydronic Heating Retrofits for Low-Rise Multifamily Buildings. Phase 1: Boiler Control Replacement and Monitoring.

摘要

The ARIES Collaborative, a U.S. Department of Energy Building America research team, partnered with NeighborWorks America affiliate Homeowners Rehab Inc. of Cambridge, Massachusetts, to implement and study improvements to the heating system in one of the nonprofits housing developments. The heating control systems in the three-building, 42-unit Columbia Cambridge Alliance for Spanish Tenants (CAST) housing development were upgraded in an effort projected to reduce heating costs 15%-25%. Homeowners Rehab Inc. recognized that heating fuel use per square foot per heating degree day in the development was excessive compared to its other properties of similar construction. Although a poorly insulated thermal envelope contributes to high energy bills, adding insulation to the exterior walls is not a cost-effective or practical option for Columbia CAST, given the desire to maintain the building's historic exterior finish; insulating the interior walls was also impractical, as it would disrupt the residents. The more cost-effective and readily available option was improving heating system performance. Efficient operation of the heating system faces several obstacles, including inflexible boiler controls, failed thermostatic radiator valves, and disregard by residents of recommended thermostat set points. In Phase 1 of the project, the boiler controls in three buildings were replaced with alternative systems, including those with more aggressive setbacks and a system that supplies heat based on apartment temperatures and outdoor temperatures. In one building, real-time apartment temperature data are available to building staff via the Internet, as is an interface allowing remote control of the heating system. Although similar multifamily energy management systems have been available for a number of years, a rigorous study quantifying the effectiveness of these features was not found. Phase 2 of the project (planned for 2012) will integrate direct control of individual radiator zones into the system. A wireless communications network will enable the central control strategy to operate the heating system efficiently by tailoring heat distribution based on space temperatures in individual zones.