Side-by-Side Thermal Tests of Modular Offices: A Validation Study of the STEM Method

Assessing the Relationship between Measurement Length and Accuracy within Steady State Co-Heating Tests

“…Baker and Dijk [38], referring to testing in outdoor test cells, similarly considered a ∆T of at least 10 K was required, with 20 K preferable. Judkoff et al [39] filtered out tests with ∆T lower than 20 • F (11 • C) when testing office cells with the PSTAR method.…”

Building America House Simulation Protocols (Revised)

“…Co-heating (Judkoff et al 2000), or infrared imaging during cold weather can provide useful information about the insulation quality of the house without damaging the building envelope. A short-term monitoring test (STEM) can provide the overall building loss coefficient and thermal mass (Judkoff et al 2000), but in most retrofit scenarios a STEM test is overly expensive and would not provide data that could be easily factored into a detailed building simulation.…”

“…An estimate of AFUE for a furnace or Heating Seasonal Performance Factor (HSPF) for a heat pump can be estimated by performing a co-heating test to determine the building loss coefficient (Judkoff et al 2000), then measuring the gas or electricity input over a period of time with known inside and outside temperatures. Because thermal mass and solar effects complicate this approach, it should ideally be conducted under near steady-state conditions at night.…”

Building America Performance Analysis Procedures for Existing Homes

“…Co-heating (Judkoff et al 2000), or infrared imaging during cold weather can provide useful information about the insulation quality of the house without damaging the building envelope. A Short-Term Monitoring Tests (STEM) can provide the overall building loss coefficient and thermal mass (Judkoff et al 2000), but in most retrofit scenarios a STEM test is overly expensive and would not provide data that could be easily factored into a building simulation.…”

“…To the extent possible, the performance characteristics (efficiency and capacity) of all spaceconditioning components (including heating system, cooling system, dehumidification, air handler, and ducts) for the Pre-Retrofit Case shall be based on physical inspections, audits, design specifications, and measured data. An estimate of Annual Fuel Utilization Efficiency (AFUE) for a furnace or Heating Seasonal Performance Factor (HSPF) for a heat pump can be estimated by performing a co-heating test to determine the building loss coefficient (Judkoff et al 2000), then measuring the gas or electricity input over a period of time with known inside and outside temperatures. Because thermal mass and solar effects complicate this approach, it should ideally be conducted under near steady-state conditions at night.…”