Residential buildings in Latvia are one of the essential heat consumers during the heating season. The majority of Latvian as well as European residential buildings were constructed within the period from 1965 to 1990. Introduction presents brief overview of current situation in Latvian and EU countries. This chapter provides overview of real energy consumption and definition of buildings technical conditions. Materials and methods are based on evaluation of standardized energy consumption in two kindergartens and multi apartment buildings including also dynamic energy simulation. Chapter on thermal performance of building envelope provides an extensive comparison of heat transfer coefficients in non-renovated buildings as well as comparison with normative values. Section on energy consumption of existing multi apartment buildings presents review of buildings real energy consumption before and after renovation. In addition this chapter evaluated indoor air quality. This study was done in order to define necessary reconstruction goals to reach European Regional Development Fund project "A New Concept for Sustainable and Nearly Zero-Energy Buildings" Nr. 1.1.1.1/16/A/007 main targets. Аннотация. Жилые здания в Латвии являются одним из основных потребителей тепла в отопительный сезон. Большинство латвийских и европейских жилых зданий были построены в период с 1965 по 1990 год. Введение представляет краткий обзор текущей ситуации в Латвии и странах ЕС. В этой главе представлен обзор реального потребления энергии и определение технических условий для зданий. Материалы и методы основаны на оценке стандартизированного потребления энергии в двух детских садах и многоквартирных домах, включая также динамическое моделирование энергии. В главе, касающейся тепловых характеристик ограждающих конструкций зданий, дано подробное сравнение коэффициентов теплоотдачи в не отреставрированных зданиях и сравнение их с нормативными значениями. В разделе об энергопотреблении существующих многоквартирных домов представлен обзор реального потребления энергии зданиями до и после модернизации. Кроме того, в этой главе дается оценка качества воздуха в помещении.

Abstract. This study focuses on assessing the contribution of the passive ground-coupled air heat exchanger system to decreasing the energy consumption of air conditioning and ventilation systems for office buildings in the Latvian climate conditions. The theoretical part of the thesis deals with methods of office building ventilation, supply air preheating and heat recovery as well as particularities of using ground-coupled air heat exchangers, their design parameters and their joint impact on the thermal performance. The engineering project part includes a ventilation system for an office building with an integrated ground-coupled air heat exchanger. By simulating energy consumption of the ventilation system for a duration of one year, the thesis analyzes the contribution of the heat exchanger to the overall energy consumption, which totals 9.53 MWh and 4.02 MWh a year, according to the desired parameters of the indoor climate. The possible alternative heat recovery solutions are investigated to reach by European Regional Development Fund projectNr.1.1.1.1/16/A/048 "NEARLY ZERO ENERGY SOLUTIONS FOR UNCLASSIFIED BUILDINGS". IntroductionBuilding ventilation and air condition systems consume a big part of total energy consumed by building mainly for heating ambient air in winter and cooling it in summer. Therefore integration of different passive systems can make a significant contribution in reducing building energy consumption.Most of the passive systems use solar energy in direct or indirect way. Directly it is used in the production of electricity and heat energy. Other types of passive systems are based on the heat recovery and preheating of incoming air. Interesting and promising technology is the use of ground-air heat exchanger. It is based on the heat exchange between the air and the pipes buried in the ground, which has a high heat capacity. At certain depth the ground temperature is lower than outside air temperature in summer, and higher than in winter. In such ground-to-air heat exchanger indirectly uses solar energy to preheat the incoming air in winter and cool it in the summer.In order to make precise evaluation of such heat exchangers the non-stationary heat transfer should be taken into account [1][2][3][4][5][6][7]. The aim of this paper is to evaluate an investment of using ground-to-air heat exchanger in reduction of energy consumption for office building heating and air conditioning systems in Latvian climatic conditions. The efficiency and calculation methodology of ground-to-air heat was already proved in late 90ies by [1,8]. However there are several studies on updated calculation models [4,5]. For example study [3] shows heat exchanger of 200mm in diameter with length of 40 m insure supply air temperature close to soil temperature.

Abstract. New concept of passive cooling of buildings is presented in this article.. In order to achieve that, it is planned to define three basic elements of the building concept -shape of building, sun movement and sustainability of the building. These parameters will serve as corner stone's also further in development of building concept. In addition not only passive cooling elements are considered during concept elaboration process but also passive building basic principles which include building location, window placement on facades, room alignment, building constructions and high comfort level. Dynamic simulation software was used in order to perform calculations, and to make conclusions on most optimal window/wall proportions and passive cooling potential. Paper presents study on multi apartment buildings renovation specifics in Latvia and its influence on total energy consumption. The necessary reconstruction goals are defined to reach European Regional Development