IBPSA2009

One of the main goals of sustainable development is the reduction of fossil fuel consumption. It can be done by applying a range of principles that help practitioners to move their projects toward the goal of natural energy resources conservation. The American Institute of Architects in their program 50»50 listed the fifty principles which when embraced individually or collectively will help to reduce the fuel consumption to 50%. One of these principles is «Energy modelling».

Simulation based control schemes for a low-energy building system are introduced and compared in this paper. The simulation of a low-energy system is firstly constructed and a fast two-stage optimisation method is proposed to find the optimal control policy in short time. A Model Predictive Control (MPC) scheme and a Hierarchical Fuzzy Rule based Control (HFRC) scheme that is tuned online by a reinforcement learning (RL) agent are introduced. The MPC scheme runs the simulation online to predict the future behaviour in order to make long-term optimal decisions.

An optimum operation scheme was applied to the thermal storage system in an actual building and evaluated using measurement data. First, the accuracy of the load prediction was verified. In a trial operation, the expected error percentage (EEP) of the sum of the daily cooling load was 9.8%, which shows the cooling load prediction is sufficiently accurate for practical use. Second, the accuracy of the system simulation of the HVAC system was verified.

To improve the energy performance of a district heating and cooling (DHC) plant, the expected performance of the plant was studied using simulations based on mathematical models. A model of the entire heat source system with an embedded module that automatically determines the on/off status of heat source equipment using cooling/heating loads was developed and validated using measured actual performance data. The mean error between the simulated and measured total energy consumption was 4.2%.

Analogy between the Microelectronics and Building industries is explored with the focus on design, commissioning and operation processes. Some issues found in the realisation of low energy buildings are highlighted and techniques gleaned from microelectronics proposed as possible solutions.

This paper presents results of a study to investigate the thermal performance of two existing houses that use rammed earth as the sole wall material and compare it with the performance of a house using insulated rammed earth walls. Indoor temperatures of the houses were hourly monitored and the monitored data were used to calibrate the simulation models.

A recently completed extension to IEA BESTEST includes further work on tests suitable for the validation of ground coupled heat transfer modules within building energy simulation software. The model described here forms part of this work. A finite difference model was prepared and applied to ground coupled heat transfer in the environs of a building for a range of geometries and boundary conditions. The model was verified by demonstrating close agreement with an analytical solution and with two independent models; it is therefore fit for purpose.

This paper compares daylight simulation results generated with two simulation programs, 3ds Max® Design 2009 and Daysim 3.0, to indoor illuminance measurements in a sidelit space. The sidelit space was in a single location, but was configured with five fenestration and glazing options, and operated under a variety of sky conditions. Both programs were given external direct and diffuse irradiances as simulation input, from which they had to predict indoor illuminances on a grid of upward facing work plane sensors and downward facing ceiling sensors.

Velux Daylight Visualizer 2 is a software tool dedicated to daylighting design and analysis. It is intended to simulate daylight transport in buildings and to aid professionals by predicting and documenting daylight levels and appearance of a space prior to realization of the building design. The critical question is whether Velux Daylight Visualizer 2 produces trustable simulations the user can be confident in. A key point to answer this question is to assess the software capability to simulate the light transport in a physically correct way.

Building simulation must be calibrated to fit the customer’s bill before applying energy saving measures. However, existing calibration methods are usually too complex to be included in building simulation software. The author has developed and implemented in DOE2.1E based building simulation software a calibration method which assists the software user in the calibration process using built-in engineering rules as well as optimization algorithms based on Marquardt-Levenberg non linear least square method.