Issue 1/2015

The paper is author’s polemic with architects about meaning of architectonic production related to the energy savings, which have become the main parameter for evaluation of buildings. Obligation to reach energy savings implies from the programs of EU, although author doesn’t mention them. The effort to achieve energy-saving building is documented by author’s initiative showed when designing heating and cooling system for building of Lothar Fischer Museum in Germany. As he did not convince the architect about completely inappropriate solution from investment and operation point of view, he managed to convince the investor and achieve the change of architectural design. The author showed not only considerable courage but also persistence, which is based on his belief that a house is either good, or bad. His attitude towards the problematic could be and should be an example for HVAC designers. They should strive for the technically optimal design solutions of HVAC systems while keeping accommodating attitude towards work of architects. It is not easy and it will probably never be. But in any case, it is a duty of HVAC designer to express and emphasize his opinion.

The paper focuses on the basic requirements and principles that apply to the designing of the smoke and heat removal systems in buildings. These systems are regularly implemented in gathering spaces such as theaters, cinemas, multipurpose halls, disco clubs, etc. and also in shops, malls, warehouses, underground spaces with a greater number of people, atriums, collective garages, etc. The necessity of the smoke and heat system installation is decided by building fire-safety consultant according to the standardized evaluation criteria. Determination of this requirement is the main basis for the designer who designs the smoke and heat removal system.

The paper deals with the Prague Heat Island, the climatic phenomena typical for all big cities. The attention is paid to its size, respectively intensity, presented is also the time evolution in the last 50 years and the expected development until the half of the next decade. Next to it, the biometeorological aspect of the phenomena is also mentioned through the physiological equivalent temperature, which is used for the first time in such a context. Considering that the big motivation for deepening the knowledge about Prague Heat Island is project „UHI“, financed by the FP7 EU program in the scope of the „Central Europe Program”, the paper mentions also the basic information about this project with a focus on Prague.

The paper deals with modelling and experimental validation of the heat pump model with cooler of the vapours and aftercooler. The first part describes model of the individual components and the whole cycle, including boundary conditions. The constructed prototype and measuring circuits are described in the second part, including placement of individual sensors. The model of the heat pump has been verified by experiments on the prototype. The mathematical model shows high correspondence with measurement for most of the operational conditions. The mean deviation of measured and calculated power outputs is 4 % for standard configuration (only evaporator and condenser). For multi-exchanger configuration the model differs from the experiment by 10 %. The validated model can be further used for optimization and simulations in another computational programs.

The use of refrigeration systems – heat pumps for heating of family houses and apartment buildings is nowadays common practice. Only the appropriately designed and operated systems provide required technical parameters, bring energy savings and assures their long life-time. However, fundamentally different are operational conditions of refrigeration system (with so called direct evaporation) which will be used as a cold source and eventually as a heat source for air-handling unit. This has been proved by negative experience with some already installed systems, which concerns especially winter season operation during zero and sub-zero temperatures of outdoor air, but also cooling during transitional and summer season operation. The author tries to share his personal experiences with designing, realization and operation of these systems up to the refrigerating capacity about 150 kW, which occupy the crucial part of our market.

Paper introduces the energy study for old building retrofit for future Centre of Low Energy Buildings in Pisek. Design of the energy efficient buildings with nonuniform user structure (combined residential, administration and technology use) requires the detailed dynamic simulations of buildings and energy system to develop the optimum concept meeting the comfort demand on one side and energy efficiency on the other side with minimized investment costs. Energy study of building retrofit for the Centre has shown how important could be knowledge on future building use in the design stage and has clarified the questionable issues for further design process (high fraction of fan power on electricity demand, suitable extent of PVT collectors use, optimum storage capacity for heat and cold and its cost benefit).

The paper deals with air-distribution in the room with the cross-section of 18 m2, where is required a steady flow with a low speed from 0,1 to 0,2 m/s. The principle of the novel solution lies in air dispersion and exhausting through the walls made from special textile perforated with holes with a diameter smaller than 1 mm. The experiments in the room for testing refrigeration furniture confirmed satisfying the design conditions.

The paper follows up the information about principle and process of standardization on the international and national level published in the issue 2/2014 of this journal. The overview of the valid national and European standards related to the field of heating and hot water production is now added to the previously described general principles.