Issue 2/2011

Article deals with different access to sequence control of boilers. There are given individual control manners theirs benefits and disadvantages. The manners of boilers sequence control are supplemented with hydraulic connections and there is described their control behaviour too.

Authors continue subsequently after the preceding publication in the VVI concerning the subject of noise in balancing dampers in their article. They solve the improvement of the balancing ability by installing a pair of dampers with different damper leaves (blades) and the different angle of their turning, in this article. The balancing ability of the pair of dampers has been specified as the dependence of so called kk value to the angle of turning individual leaves of dampers, in the conclusion of the article. It has experimentally been evidenced that the linear balancing characteristic can be achieved with a proper design of the pair of dampers. There is shown a significant reduction of noise in the balancing unit designed in this way, in this article. This shall be specified in detail in the following subsequent publication.

Temperature profiles in the non-isothermal flat jet of the cold air along the vertical wall are summarized in the experimental study. There were compared results determined for two slot outlets with different widths, and measured at two velocities and different temperatures of the supplied air. The scope of conditions is expressed in values Re = 1333 and Ar = 0.02–0.87 with the slot width as the characteristic dimension. The comprehensive generalization of results should require the analysis of the Ar criterion impact.

The author shows specific results obtained during measurements of the inside micro–climate parameters in already operated aqua-parks and he concurrently analyzes reasons of problems found out during the operation of the HVAC equipment, in his article.

Looking at the renewable energy support policy implemented until now in Europe, the most attention have been paid to the support of the electricity production. However, increasingly the support of the heat production from the renewable energy sources is being discussed. The text below provides an overview of the policy instruments applied historically in the EU member states and more detailed description of a few policy application examples. Further, some of the policy instruments that could be potentially applied in the Czech Republic in the future have been evaluated from the point of view of economic efficiency, effectiveness and administrative feasibility. The analysis shows that the instruments successful in increasing the share of renewable energy in the electricity production cannot be implemented without significant modifications at the distributed heat market.

A close cooperation between the fire–prevention officer and the HVAC specialist results in the securing safety evacuation of persons from a burning house and the intervention of fire fighting units. The author acquaints readers with the existing situation of the legislature related in this problem, in his contribution. He refers to the substantial problem, which consists in differences between required values included in valid Czech standards CSN 73 0802 “Building Fire Safety” concerning non-production buildings and CSN 73 0804 concerning production buildings. Further, we draw your attention to the discrepancy in certain points between the valid standard CSN EN 12101–6 of the Czech Republic, which is adhered in Europe and the aforementioned standards of the Czech Republic. This situation causes considerable problems during the designing and implementation of such equipment, in many events. The author states recommended procedures in two events and process principles during the design.

The author describes a rare heating system situated in the building of Autoclub in Prague that is operable even it has been operated for forty years, in his contribution. Further, he draws the attention near to circumstances of the period of time under which measurements of properties of angular pipe distributions were in progress with the aim to verify their utilization in the practice.