Issue 3/2014

The article deals with the use of wastewater. There are defined the different types of wastewater, followed by their re-use in houses, apartments or industry, which may be the proper cleaning of the water, the profits of their potential energy that can be used to produce heat, cold or electricity production.

The paper summarizes experience of the authors with use of predictive control for heating networks operation in buildings. Four pilot applications of predictive controller in practice are described in the text and the assets of the predictive control are evaluated. The close attention is paid also to the steps which are necessary for successful use of predictive control.

The author deals with different combustible properties of biomass and coal. He describes specific approaches to combustion and fabrication of burners and to the method of burning air supply, in particular. He applies himself to new legislative requirements for small heat sources ensuing from the novelty of Act on Environmental Air Protection.

Authors describe the design of solar kombi-plus system primarily determined for the ensuring a part of heat for the absorptive cooling the water in the pond (pool) in the pavilion of seals and penguins in the climatic warm period, in their contribution. If the pond water need not to be cooled, the produced warm is to be used for the WSW preparation or for the additional heating.

The paper presents simulational analysis of the ground heat pump with subcooler for increasing the efficiency of the hot water preparation. The mathematical model of the heat pump with subcooler was created for simulation environment TRNS YS. In theory the subcooler increases the heat output of the heat pump by 10 to 25 % without increase of the power input. Simulations were performed to compare operation of a standard heat pump and identical heat pump with subcooler in the system of heat water preparation. The avarage electric energy saving for the hot water preparation is 9 %, the seasonal heating performance factor is 10 % higher.

The paper deals with CFD simulation of pressure losses of capillary mats. The emphasis is put on the frictional pressure losses for laminar flow in the capillary tubes and on the dynamic pressure losses in the dividing and merging of the flows, where the regime of the flow is changing. The relations of the local loss coefficient for dividing and merging flows and also of the friction coefficient for unstable laminar flow were obtained using CFD simulations.

The paper deals with the noise of air distribution elements of the HVAC systems designed for spaces with high acoustic requirements, whose limits of the background noise are specified in the standard ČSN 73 0526. The design of the air distribution must deal with three issues at the same time. Noise reduction in the space, air flow range (respectively desired air velocity in the occupant regions) and last, but not least, the generation of aerodynamic noise by the air flowing from the distribution elements. This leads to solving three equations dependent on each other, whose character is mathematically different.

The published paper summarizes the crucial information about the actual topic – garage ventilation in the Czech Republic. The contribution is divided into three parts, due to the broad scope of the matters. The series of the papers is based on the legal and normative enactments. It reflects the new situation of natural gas powered vehicles parking possibilities and it discusses every ventilation system which can be found in garages. It deals with design principles of service ventilation, definition of emergency ventilation and basics of fire ventilation. The paper also deals with related issues such as control systems, operating regimes, detection and monitoring of pollutants, explosive atmosphere risk assessment and protocol determining external influences. The contribution is aimed not only to HVAC designers, but also to architects and designers of all related construction fields. Valuable information can be found also by the other interested groups such as investors, developers, suppliers, operators, building authorities, involved state administration bodies, etc.