Issue 5/2023

The article compares the expected and real operation of a heating and cooling system in a production hall. A real-life example is used to demonstrate the benefits of integrated building design compared to the conventional, so-called “by profession” design. The paper also discusses boundary conditions and their influence on the design efficiency, in particular, the borehole temperature and the temperature gradient of the heating and cooling system.

In agriculture, the harvesting and processing of crop production generates significant amount of phytomass that can be used for energy or material purposes. These are mainly hay from unused permanent grasslands and straw. There are around 1 million hectares of permanent grasslands, around 1.3 million sown hectares of cereals, and around 400 000 sown hectares of rapeseed per year. Of this, around 5.5 to 6.7 million tons of hay and straw can be used for energy purposes annually. Straw and hay can be burnt in the form of bales or pellets and suitable equipment has been developed and tested for such t echnologies.

Including moisture transfer in building simulation models would allow for assessment of the risks associated with moisture exposure of building materials and building users. Modeling moisture transfer in a building requires, among other things, to define moisture sources acting inside the building, to model moisture transfer between the internal environment and the building enclosure and internal building components, to model transport and retention of moisture within building components, to model moisture transfer through leakages in the building enclosure, and to model moisture transfer due to air flows between internal environment and external environment or neighboring zones. This paper deals with the validation of a simplified dynamic hygrothermal building model. At first, the hygro-thermal model of the whole building is compared with measured data from IEA Annex 41. In the second step, the simplified moisture transport model is compared with measured data from a dynamic laboratory experiment performed with samples of spruce wood.

The ENERGO 2021 sample survey updated the basic data on consumption of fuels and energy carriers in Czech households according to the purpose of their use. This paper presents an overview of the most important findings of the sur vey concerning fuel and energ y use in dwellings loca ted in family houses.

The reduction of energy consumption for heating a building with very low energy consumption and high indoor environmental quality requirements can be supported by zone ventilation, where fresh air can be supplied to each occupied room according to the required CO 2 concentration. The paper presents a method of zone ventilation control in a family house in the sense of controlling the dampers and the total volume flow of outdoor air through the ventilation unit. A pilot installation of zone ventilation in a family house demonstrated that zone ventilation, where control dampers are installed individually for each room, allows targeted ventilation of occupied rooms and minimises ventilation in the other rooms. This solution ensures the desired indoor environmental quality and improves the air quality in case of a larger number of occupant s in the main ventila ted zone.

The paper describes a method to determine the sensible effectiveness of rotary regenerative heat exchangers for heat recovery. Nine heat exchangers with different thermal wheel geometries were analysed within the study. Based on the performed experiments, the dependence of the sensible effectiveness on the thermal wheel rotation speed, and the maximum sensible effectiveness, were evaluated. The measured values are compared with the results obtained on the basis of the a vailable correlations.

This paper describes a method for determining the volume of a storage heater or hot water storage tank according to the peak demand, based on the data from measurement and analysis of hot water consumption and demand patterns in various, mainly residential, buildings. The calculation relationships used in the paper reflect the measurements that were carried out as a part of this analysis.

-