Weather correlations to calculate infiltration rates for U. S. commercial building energy models

Abstract

As building envelope performance improves, a greater percentage of building energy loss will occur through envelope leakage. Although the energy impacts of infiltration on building energy use can be significant, current energy simulation software have limited ability to accurately account for envelope infiltration and the impacts of improved airtightness. This paper extends previous work by the National Institute of Standards and Technology that developed a set of EnergyPlus inputs for modeling infiltration in several commercial reference buildings using Chicago weather. The current work includes cities in seven additional climate zones and uses the updated versions of the prototype commercial building types developed by the Pacific Northwest National Laboratory for the U. S. Department of Energy. Comparisons were made between the predicted infiltration rates using three representations of the commercial building types: PNNL EnergyPlus models, CONTAM models, and EnergyPlus models using the infiltration inputs developed in this paper. The newly developed infiltration inputs in EnergyPlus yielded average annual increases of 3 % and 8 % in the HVAC electrical and gas use, respectively, over the original infiltration inputs in the PNNL EnergyPlus models. When analyzing the benefits of building envelope airtightening, greater HVAC energy savings were predicted using the newly developed infiltration inputs in EnergyPlus compared with using the original infiltration inputs. These results indicate that the effects of infiltration on HVAC energy use can be significant and that infiltration can and should be better accounted for in whole-building energy models.

Cross-platform, Public Domain Simulation Tools for Performing Parametric IAQ and Energy Analysis

“…The Mid-Rise Apartment building model is based on the EnergyPlus representation selected from the set of U.S. Department of Energy (DOE) Commercial Reference Building models developed by the National Renewable Energy Laboratory (NREL). NIST developed a corresponding CONTAM representation of this building (Lisa C Ng et al, 2012) to be compatible with the co-simulation approach outlined in Dols et al (2016). Both models were modified to include stair and elevator shafts that enable simulation of stack flows that can be particularly important to infiltration, energy use and contaminant transport in multistory buildings.…”

“…Generally, infiltration and interzone airflows are user-specified, i.e., not pressure-dependent as in CONTAM, and are not required to be in balance with system airflow rates. Typically, infiltration is modelled based on correlations associated with rectangular, low-rise residential buildings or may be assumed to be constant, but better methods are available (Lisa C. Ng et al, 2018).…”

Indoor air quality modelling and measurements of a studio apartment with a mechanical exhaust system

“…It has been used by authors of many studies to determine the contaminant levels and test different types of ventilation systems [23][24][25][26][27][28][29] which is why it was chosen for this study. Hamdani et al [26] used the program to study the effect of natural ventilation on the indoor air quality.…”

Assessing the Energy and Indoor Air Quality Performance for a Three-Story Building Using an Integrated Model, Part One: The Need for Integration

“…Combined methods of modeling energy and airflow have been used in some energy simulation tools. These models are capable of simultaneously simulating energy and multi-zone airflow, but the limitation regarding accurate airflow calculations is the main problem [5]. Gowri et al [6] proposed a method for estimating the infiltration in commercial buildings using EnergyPlus, which considers the effects of wind but not temperature, thus ignoring the stack effect and key building features, such as vertical shafts, in infiltration models.…”