Issue 3/2017

The Civil Code has brought many changes in the regulation of relations addressing the execution of a construction or related activities, such as preparation of project documentation in various stages. It newly regulates contract for work, which is the type of contract most commonly used in relations arising in connection with construction works. The new regulation of contract for work is based on the regulation contained in the Commercial Code, which was repealed by the Civil Code effective as of January 1, 2014. It newly addresses also legal consequences in case if performance of the contract for work does not comply with expectations of the parties, when it is defective.

The article introduces one of the particularity of the predictive controller for heating control at the building of the Faculty of Electrical Engineering (FEE) and the Faculty of Mechanical Engineering (FME), Czech Technical University (CTU) in Prague. The building is characteristic by the use of ceiling heating system type Crittall, with a very slow thermal inertia. District heat is delivered from a central heating plant. On the real example is shown how to take advantage of the predictive control for scheduling of heat consumption, to ensure compliance with the contracted power capacity, without violating of thermal comfort in the building. The predictive controller yields in savings of not only supplied heat, but it can also be used to reduce reserved power capacity, because it assures spreading of the performance over the time, i.e. during periods of increased energy demand and ensures not exceeding of the contracted limits.

From 1st April 2017 on, the labelling with energy labels is mandatory newly also for small hot-water solidfuel boilers. This obligation concerns also systems consisting of a hot-water boiler, of a backup heat source (another boiler or solid fuel stove, heat pump, gas condensing boiler), temperature controllers or solar panels. Quite a great deal of discussion and confusion prevails around determination of the energy efficiency class of multi-fuel boilers, which are certified for combustion of both biomass and fossil fuels. Considering the complexity of the issue, the article only deals with labelling of individual boilers, and not systems.

The article discusses basic methods to assess the energy performance of condensing gas boilers. It introduces methods and ways that are based on relevant standards and regulations. These methods are carried out in laboratory conditions of accredited testing facilities, they achieve different precision and they are useful for development of given technical level of gas boilers. The article describes a new methodology for determining the seasonal energy efficiency of heating, which proceeds from EN 15 502-1:2012+A1:2015 (this standard has been translated and transposed as ČSN EN15502-1+A1:2017) and is the basis for assessment according to the ERP guidelines and so called labeling of gas condensing boilers. The paper presents a universal assessment methodology that makes it possible to informatively assess differences in energy performance of condensing boiler in the heating system, which the previous methodologies failed to distinguish. Thus the different factors can be assessed, eventual proposals can be compared and appropriate solution can be optimized already in the design stage of the project. Therefore, this methodology can be a suitable complement to the other assessing methods.

The article deals with the air temperature in the Czech Republic in the heating season and seeks to answer the question whether we really belong to the area with colder climate, where we have been ranked by the EU legislation introducing the labeling of hea t sources.

The paper thematically follows-up on the paper published in the previous issue of VVI journal – Design of Water Meter with Respect to the Achieved Accuracy. The author highlights in the follow-up the influence of the water meter installing execution on the achieved measurement accuracy. The used type of gasket or screw fitting is respected.

The introductory part of the article discusses the EU Commission Regulations no. 811 to 814/2013 regarding heaters of domestic hot water (DHW) and heat sources for heating in relation to the indicated profiles of heat and DHW consumption. Second part presents measurement of DHW consumption in several apartment buildings and its evaluation leading to determination of DHW consumption curves. Consequent evaluation compares the legisla tive and real results from the point of view of utiliza tion for different building types.

The paper deals with the issue of the irradiation prediction. It describes the current state of forecasting services and their use with regard to photovoltaic systems. It presents the basic methods for evaluation of the irradiation prediction accuracy. It also presents the results of these methods for five forecasting data sources during the whole year 2016.

Ventilation concept is a document that provides basic orientation in the issue of ventilation of buildings with presence of occupants. It is intended for all persons employed in construction, whose activities affect the formation of the building indoor environment – builders, users, developers, architects, designers, supply companies, operators and employees of the state administration (construction administration offices etc.). It serves especially for the preparatory phase of documentation, when the ventilation concept is chosen, though it can be used in all the stages of the design process and its implementation. It will be applied for design of new buildings, renovations and changes in use of buildings, especially in the case of windows exchange. The target of the artic le is to acquaint readers with the content of this new document .