optimization

With rising insulation standards and air tightness in buildings, the use of mechanical ventilation becomes more relevant. In this context, energy recovery offers a significant contribution to the decarbonisation of building operations. Heat recovery systems are widely spread in residential ventilation. Moreover, enthalpy exchangers recovering sensible and latent heat have an increasing share of use in residential ventilation, especially in cold climates, as they not only reduce the energy demand but also increase the indoor air humidity in winter seasons.

The control of heat losses, inwards/out, in nearly zero energy buildings is of high importance. The transmission losses through the building envelope are easily reduced using larger amounts of insulation. Calculation of the impact of this action on the total energy demand of the building, is quite standard. It’s however much more difficult to determine the efficiency of actions to increase the airtightness of the building and the influence of the ventilation system.

The paper presents optimization model of the chilled water based data center cooling system. The optimization procedure includes system technological and mathematical model, limiting conditions and optimization criterion, which in this case is annual power consumption minimum. The cooling system model is defined by constant parameters and decision variables and consists of aircooled chiller, independent external freecooling heat exchanger (drycooler), computer room air handling unit (CRAH) and constant flow chilled water system with circulation pump.

Since naturally ventilated buildings respond to site conditions and microclimate, there is no ”one set of spe-cific criteria” for every naturally ventilated building. So natural ventilation should be optimized to deal with ther-mal comfort in passive buildings during hot season.

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%.

For the purpose of reducing the room air-conditioners’ energy consumption, an energy saving control method is proposed formerly. In this paper its energy saving effect is confirmed through experiments conducted in six office rooms in actual use. The experiment results show that the air-conditioners controlled by the present energy saving control logic and parameter settings can save electric power up to 3.0% compared to ordinary control.

The present paper proposes an optimal operational strategy of an actual HVAC system with a seasonal underground thermal storage system using simulation. The simulation is a powerful tool for the system because it is difficult to try various operational methods experimentally in the actual system due to the long heat transfer time in the underground.

Facades must meet with continuously increasing requirements concerning design quality and technical performance. It will be shown that neither extremely simplifying nor highly detailed simulation tools with complete geometrical representation really help to develop new facade types during the early stages of design. Due to simplified physical modelling, conceptual variations may not be adequately represented and this means that different properties cannot be seen.

A computerized model, CoED (Collaboration Enhancing among Design participants) was developed, focusing on the relationships between designers, design variables and design phases. It uses optimization, based on Genetic Algorithm, to decompose these relationships into workgroups of relevant designers and design issues, for each design phase. It identifies intersecting issues between designers, allowing them to be aware of the effects of their decisions on issues relevant to others and enlightening tradeoff options for each one so that conflicts may be avoided and controlled.

The aim of the present study was to determine the applicability of a genetic algorithm for the optimization of daylighting systems, as well as the requirements for the lighting simulations to be used. Furthermore, by testing the daylighting performance of a building's facade when several parameters are allowed to change simultaneously, the results were used as a complement of previous parametric studies. The goal of the optimization was to maximize energy savings by reducing visual discomfort while maintaining good daylight penetration.