Techniques to Estimate Commercial Building Infiltration Rates

The estimation of low-rise, residential building infiltration rates using envelope airtightness values from whole building fan pressurization tests has been the subject of much interest and research for several decades, constituting a major topic of discussion during the early years of the AIVC. A number of empirical and model-based methods were developed, with their predictive accuracy evaluated in field studies around the world.

Modeling Dynamic Behavior of Volatile Organic Compounds in a Zero Energy Building

With increasing building airtightness, the design of an adequate ventilation system gains importance. The first generation of ventilation systems, based on continuous supply of the nominal airflow rate, are now being replaced by Demand Controlled Ventilation (DCV). These systems, often H2O and/or CO2 controlled, do not take into account the emissions of Volatile Organic Compounds (VOCs) to the indoor environment.

COMIS - an international multizone air-flow and contaminant transport model.

A number of interzonal models have been developed to calculate air flows and pollutant transport mechanisms in both single and multizone buildings. A recent development in multizone air-flow modeling, the COMIS model, has a number of capabilities that go beyond previous models, much as COMIS can be used as either a stand-alone air-flow model with input and output features or as an infiltration module for thermal building simulation programs. COMIS was designed during a 12 month workshop at Lawrence Berkeley National Laboratory (LBNL) in 1988-89.

Coupling strategies for combined simulation using multizone and building envelope models

Combined heat, air, moisture and pollutant simulations (CHAMPS) at the building system level are essential for improving energy efficiency and indoor environmental quality. This paper discusses the technical challenges and possible solutions to the problem of coupling an envelope model (CHAMSBES) with a multizone/network model for inter-zonal air and pollutant transport. A representative multizone solver was written, which solves the coupled heat, air, moisture and pollutant transport equations.

Comparison of three IAQ calculation methods

Calculating contaminant concentrations in or the required ventilation for a space has been a difficult and confusing part in the application of the IAQ Procedure of ANSI/ASHRAE Standard 62.1-2004; Ventilation for Acceptable Indoor Air Quality. Appendix D of ASRAE Standard 62 presents one method for performing these calculations, but it is limited to the steady-state analysis of a single zone. More recently, two software tools have been developed by the United States National Institute of Standards and Technology (NIST) to facilitate these calculations and to include transient effects.

Development and application of test cases for comparing vertical ground heat exchanger models

The main objective of this paper is to establish a set of test cases for analytical verifications and intermodel comparisons of ground heat exchanger (GHX) models used in building simulation programs. Several test cases are suggested. They range from steady-state heat rejection in a single borehole to varying hourly loads with large yearly thermal imbalance in multiple borehole configurations.

Computer model of a university building using the EnergyPlus program

This paper presents the development of a computer model of an academic building using the EnergyPlus program and its calibration with monitored data. The new Concordia Sciences Building (CSB), located in Montreal, has a total floor area of 32,000 m2. The size and the complexity of the heating, ventilation and air conditioning (HVAC) and heat recovery systems make the modeling process a challenge and an excellent opportunity to evaluate the capabilities and features of EnergyPlus in this particular context.

Study on the air movement character in solar wall system

A mathematical model for simulating airflow in solar channel of the insulated Trombe solar wall system is proposed. It is assumed the glazing is isothermal and the solar heat absorbed by the wall is transferred to  the air in the channel with a constant flux by natural convection. The mass, momentum and energy  conservation equations are discretized and solved using the finite difference control volume method. An experimental study of solar chimney was used to validate the proposed mathematical model.

A simplified hot water distribution system model

Water heating in the U.S. has been identified as a major component of total energy consumption used in buildings, mostly coming from the residential sector at around 11%. A potential opportunity for energy savings in water heating systems is to improve the design of hot water distribution systems (HWDS). Due to the complex heat losses of HWDS, models are needed to optimize HWDS by reducing heat losses. There are three models currently used to simulate thermal performance of hot water distribution systems (HWDS): HWSim, ORNLHWDS, and TRNSYS.

Absorption of solar radiation in thick and multilayered glazing

Given the major role played by windows with regard to energy losses and gains from buildings in respectively cold and hot climates, accurate prediction of the heat transfer through its glazing materials is of great importance in building energy simulation. In most of the building energy simulation programs, solar radiation absorption inside glazing layers is usually treated considering that all the radiation is uniformly absorbed in the glazing.

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