Joanna Ferdyn-Grygierek

The Improvement of Thermal Comfort and Air Quality in the Historic Assembly Hall of a University

This paper presents the concept of air-conditioning and thermal environment of the monumental historic auditorium at the University of Wrocław. There are several requirements to be taken into account concerning the air-conditioning, since this is both a museum and an assembly hall. To maintain the required air parameters, as well as good air quality, comfort air-conditioning was designed, using an all-air system with heat recovery. A heat–humidity balance for the auditorium using dynamic thermal calculations was derived by use of a computer program – the building thermal model ESP-r. The concept of the air distribution in the auditorium was validated and improved, numerically predicting the flow of air, heat, humidity and carbon dioxide, using the computer code CFD ANSYS Airpak. This confirmed that the air-conditioning can ensure the airing of the auditorium and the maintaining of air parameters within the required ranges.

Heat demand and air exchange in a multifamily building — simulation with elements of validation

The experiment providing data on the energy demand and air exchange in the flat located in the multifamily building is presented in the paper. The measurement was carried out during 3 weeks in winter. The total energy consumption necessary for flat heating was measured continuously. During the same time air change rate in the flat was measured by means of tracer gas concentration decay methods. After measurements were finished the energy demand and ventilating airflows were calculated assuming the same weather data variation as measured during the experiment, using the ESP-r software. Contam program was used for the air infiltration simulation, giving more detailed results about the ventilation airflows within the tested object. Comparison was made between numerical results and measured data over the given cycle and a good correlation of results has been achieved. Practical applications: Simulation methods can be an alternative to the assessment of energy consumption or heat demand in buildings when the direct measurement is impossible or difficult. A good agreement of simulation and measurement results is reached when the average values of the results are compared for a longer period of time.

Multi-Objectives Optimization of Ventilation Controllers for Passive Cooling in Residential Buildings

An inappropriate indoor climate, mostly indoor temperature, may cause occupants’ discomfort. There are a great number of air conditioning systems that make it possible to maintain the required thermal comfort. Their installation, however, involves high investment costs and high energy demand. The study analyses the possibilities of limiting too high a temperature in residential buildings using passive cooling by means of ventilation with ambient cool air. A fuzzy logic controller whose aim is to control mechanical ventilation has been proposed and optimized. In order to optimize the controller, the modified Multiobjective Evolutionary Algorithm, based on the Strength Pareto Evolutionary Algorithm, has been adopted. The optimization algorithm has been implemented in MATLAB®, which is coupled by MLE+ with EnergyPlus for performing dynamic co-simulation between the programs. The example of a single detached building shows that the occupants’ thermal comfort in a transitional climate may improve significantly owing to mechanical ventilation controlled by the suggested fuzzy logic controller. When the system is connected to the traditional cooling system, it may further bring about a decrease in cooling demand.