Field Notes Summer 2019
Posted by Dana Rider | Date June 17, 2019
Commercial boiler control tune-ups
Background: With the increasing dominance of high-efficiency condensing boilers in commercial buildings, expanding the scope of boiler tune-ups to include control optimization provides an important opportunity to update CIP programs and increase savings per participant. This project will quantify actual savings achieved through such control adjustments for condensing boilers.
Researchers will develop and field test an expanded scope commercial boiler tune-up protocol that goes beyond burner adjustments to provide a comprehensive review of adjustments to boiler control settings that increase energy savings. Per their summer of 2019 update, the project team held meetings and phone interviews with professionals from 13 local organizations to assess the boiler optimization service market and plan for field monitoring.
Research update: Researchers have now selected sites for field testing. They worked with five contractors to recruit 18 sites for the study. They have been monitoring the sites, and control tune-ups will begin this summer and continue through the 2019–2020 winter.
The sites selected include a combination of apartment buildings and schools. Researchers are monitoring gas use and a number of boiler system operating conditions so that the results of the test can be used to update the state Technical Reference Manual with boiler control adjustment measures.
Learn more on the project page.
Low-rise multifamily energy code study
Background: Interpretation and enforcement of energy codes often differs across jurisdictions, and because of those differences, complying with energy code is generally more difficult than it needs to be. This study will increase understanding of current practices and opportunities for improving energy efficiency in multifamily buildings — a crucial first step in standardizing the code to benefit building owners, designers, contractors, and occupants.
Research update: CEE researchers recently performed a unique guarded blower door test in southern Minnesota that allowed them to sidestep many of the traditional setbacks of blower door tests in multifamily buildings. They used blower doors in every unit and building exit at once, to neutralize air flow between units. This test was unique because it included the largest number of “garden style” building units ever tested with this approach in the Midwest.
Senior Mechanical Engineer Russ Landry presented an update on the project at the 2019 National Energy Codes Conference, which took place the last week of May in Denver, Colorado.
Learn more on the project page.
Racked tankless water heaters
Background: More than two-thirds of multifamily housing units in Minnesota are served by large, storage-based, commercial gas water heaters or dedicated boilers tied to an indirect storage tank. These systems are inefficient compared to many modern options. This project will conduct an evaluation of central condensing tankless water heating systems (CCTWHs), whose high turndown, controls, and modular design yield more consistent operation and significantly reduce system standby losses. Manufacturers of CCTHWs claim they yield energy savings of up to 40% over storage-based systems.
The goal of this study is to verify the energy savings potential of CCTWHs in Minnesota multifamily housing, quantify benefits and potential drawbacks, and extrapolate to other sectors.
Research update: Two sites have been selected for monitoring and installation of CCTWHs. Data collection is underway at one of the two sites to establish a baseline of current conditions for comparison after installation. A second site is ready for installation, which will happen soon.
Researchers collected bids from multiple contractors for installation, so once all of the baseline data collection is done, they will be ready to install. The baseline data will be very useful because it covered a facet of multifamily energy use (hot water) into which the field generally lacks insight, since not many sites have been monitored in the level of detail before.
Learn more on the project page.
Field and market assessment of heat pump clothes dryers
Background: The fundamentals of clothes dryers have changed very little since they were first introduced in the 1940s. Today, nearly all single-family homes in the upper Midwest have a clothes dryer, and more than 80 percent of these use electric resistance heat to dry clothes. Heat pump clothes dryers hold potential for significant electricity savings by pulling air from the surrounding space to heat clothes, rather than using electric resistance.
This study was designed to compare heat pump clothes driers to conventional electric driers through field tests in single-family homes. This involves equipment monitoring and research to better understand consumer experience with the new technology. Historically, only limited data has been available for dryers in the single-family home market in Minnesota. As dryer technologies advance, user behavior and desires will have a larger impact on the dryer settings and performance, impacting energy use and savings potential.
Research update: Eight field single-family sites were selected for installations, seven of which are currently being monitored to collect baseline data on conventional dryers for performance comparison. A heat pump clothes dryer has already been installed at one site and is measuring the first phase of comparison data. The other seven heat pump clothes dryers will be installed this summer. The baseline data currently being collected is significant because it captures the range of clothes dryer usage.
Learn more on the project page.