In this paper, the mathematical model of a HVAC (Heating, Ventilation and Air-Conditioning) equipment is described. This system is inserted into a computer code developed in Matlab/Simulink platform which is devoted to the analysis of building thermal behavior and HVAC closed-loop control performance. The model is presented in terms of non-linear state-space equations that represent the energy and mass balances for each HVAC component. Two control loop structures are described and analyzed. The IMC structure is used for the PID controllers tuning procedure.
Earth-to-Air Heat Exchanger (ETAHE) technology has been implemented in many mechanical ventilation systems. A literature review revealed that recent advancements in ETAHE modeling were focused on simulating heat conduction in soil. Air temperatures along the duct length were determined by calculating heat convection on the ETAHE duct surfaces using various empirical correlations. Comparison of the correlations for typical ETAHE in mechanical ventilation systems revealed that large discrepancy exists among them.
An optimal controller for auxiliary heating of passive solar buildings and commercial buildings with high internal gains is tested in simulation. Some of the most restrictive simplifications that were used in previous studies of that controller (Kummert et al., 2001) are lifted: the controller is applied to a multizone building, and a detailed model is used for the HVAC system. The model-based control algorithm is not modified.
Tall buildings pose unique challenges for simulation software and modelers. Environmental factors such as air temperature and wind speed change with altitude. The urban environment imposes additional environmental factors because of shading and reflections from surrounding buildings. The large scale of tall buildings can result in excessive input data and prohibitive run times. EnergyPlus was used to compare the energy impacts of several environmental factors that vary with altitude.
CEN TC247 has prepared draft standards for main types of room controllers. These standards include a performance testing procedure that was designed to facilitate the introduction on the market of electronic controllers.
A simplified optimization process (SOP) for determining set points is proposed and evaluated using the monitoring data and model of an existing VAV system. Controller set points, such as supply air temperature, supply duct static pressure, and chilled water supply temperature, are determined by this proposed SOP in order to minimize energy use while respecting thermal comfort. Zone air temperatures are also considered in order to obtain further energy savings.
The models for photovoltaic (PV) systems currently in ESP-r prove very useful in estimating the electrical and thermal impact of building-integrated photovoltaics. However, while they represent well the impact of photovoltaics on the building’s thermal energy balance, they may lack in accuracy in the prediction of the system’s energy production.
The introduction of EU directives 2002/91/EC and 2003/87/EC both prompt a reduction in energy consumption from European buildings. Buildings account for 50% of European energy use. Traditional prescriptive based approaches to building energy performance have not yielded desired energy savings. In addition, energy consumption is seldom compared with design intent. A whole building life cycle performance based approach is ultimately required.This paper introduces and demonstrates Environmental Effectiveness Ratios.
This paper complements a previous publication in the Building Simulation Conference series by identifying where perceptualization techniques can improve data presentation and assist with the interpretation of the underlying performance message. The paper describes hypotheses that were tested in practice via a performance display prototype. Intended future work is summarised.
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