English

In winter, when the external air temperature is below zero, there is a risk of damage to coils in a closed type cooling tower due to freezing of cooling water. In warm climates, a method of draining cooling water from the coil can not be adopted to prevent freezing because a cooling load exists even in winter. It is necessary to make warm water circulate through the coil in closed type cooling tower. In this case, it isn’t clear when to operate an electric heater and a circulating warm water pump.

The presented paper reports on the application of a method for the numerical prediction of temperatures within and around structural passive cooling components. The recently developed method named the three-dimensional numerical generation of response factors NGRF (Zoras et al., 2009) was claimed to be fast, accurate and flexible as a result of incorporating elements of the response factor method into a finite volume technique based numerical model. Initially, a ‘pre-processing’ procedure is required to generate a certain number of hours, e.g.

In building simulation tools differential equations are widely used to model physical phenomena of components such as walls, air and any kind of system component in the building. Especially when simulation is used to study and optimise system control, the models used are mainly transient models solving differential equations in order to represent correctly the transient behaviour of the whole control loop. The TRNSYS simulation environment is a powerful tool allowing the simulation of a large number of problems.

This paper deals with the evaluation of different simulation approaches to kitchen ventilation modelling. Multi-zone, CFD and zonal approach are discussed.  The investigation moves its steps from the analysis of a controlled ventilation system intended for individual and collective housing. The question of natural ventilation being able of ensuring ventilation rates consistent with acceptable indoor air quality is dealt with. Buildings have become increasingly airproof and natural ventilation, as it will be presented, may result inadequate.

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.