Proceedings of REHVA Annual Conference "Advanced HVAC and Natural Gas Technologies"
Dear Colleagues, It is my great pleasure to invite you to the REHVA Annual Meeting and the Conference on Advanced HVAC and Natural Gas Technologies which takes place this spring in one of the Baltic States – Riga, Latvia on May 6–9, 2015. This year, Latvia, for the first time, is assuming the Presidency of the Council of the European Union and I am very honored to meet the leading international scientific and engineering colleagues and friends in the field of Heating, Ventilating and Air-Conditioning (HVAC) during this historical moment. “We welcome you to Riga - the place where knowledge sharing and experience inspires for new cooperation and further industry development.” These proceedings include 38 scientific papers from 16 countries. Presented studies cover such topical subjects as energy efficient buildings, indoor climate, safe and sustainable energy supply and production. All papers have high scientific quality as well practical industrial application. I would like to thank the authors for their valuable contribution to the proceedings of “Advanced HVAC and Natural Gas Technologies”. Professor Egils Dzelzitis President of Organizing Committee in Riga Fellow REHVA, Fellow ASHRAE and REHVA Vice-President
Towards nearly-zero energy buildings: HVAC system’s performances in the expected operative scenarios of Turin Energy Centre
This paper shows the process of minimization of delivered energy, primary energy consumption and carbon dioxide emissions for the Turin Energy Centre, a building to be realized in the city of Turin in 2015. The optimization is divided into two steps, firstly operating on the distribution of the functions of spaces, the loads and the HVAC systems in the building, and then, chosen the functional scenario, modifying the generation system. The result is the combination of building’s operative functions and generation systems that minimizes consumptions and emissions, neglecting accumulation and partial load dynamics.
Performance of Heat Recovery Ventilation System with Ground Source Brine Heat Exchanger Pre-Heating System in the Context of nZEB
The paper analyzes effectiveness of the ventilation unit pre-heating system with a ground source brine heat exchanger in a nearly zero energy building in Estonia. Focus is on the analysis of measured energy usage and possible effects on the energy usage of alternative solutions of the ventilation pre-heating system in terms of nearly zero energy building. The studied building was planned and realized according to the international passive house concept. To further lower the energy demand, the building was equipped with a solar thermal system and a photovoltaic solar system to cover the total final energy demand of the building, making it nearly zero energy building. The ventilation system is equipped with temperature and relative humidity sensors to measure supply, extract, exhaust air parameters and air parameters before and after the pre-heating system. Energy usage to pre-heat the ventilation airflow with a ground source brine heat exchanger was also measured. Our results show that annual energy used for pre-heating the ventilation airflow is around 420 kWh, which makes about 3% of the building’s total energy usage. The efficiency of the ventilation unit heat exchanger was over 80 % in the winter season due to the pre-heating system.
Evaluation of Indoor Environment in Apartment Buildings Before and After their Refurbishment
The objective of the study is to analyse and evaluate the indoor environment of the apartment buildings before and after their refurbishment. Thermal comfort and indoor air quality were taken into consideration based on both objective and subjective evaluation. Thermal indoor environment was evaluated in six blocks of dwelling buildings situated in Slovakia. Evaluation of the thermal indoor environment was based on the recording of the indoor temperature and the relative humidity before and after refurbishment. The subjective evaluation was based on a questionnaire survey, which includes data such as the thermal perception, inhabitant’s behaviour and personal background of 244 respondents living in the buildings before refurbishment and 236 respondents living in the buildings after refurbishment.
Comparison of Simplified and Detailed Window Models in Energy Simulations
The purpose of this study is to quantify the gap between the calculated energy need of a building model with simplified and detailed windows and suggest a method for reducing the gap. We composed a model of a detached house in the cold climate of Estonia and studied its energy needs with triple and quadruple windows. Standard window models resulted in heating need lower by up to 7% and cooling need higher by up to 23%. In case of triple windows multiplying the U-value of standard window models by 1.15 minimized the mismatch in the calculated energy needs with different window models.
Simulation Study of Solar Thermal and Photovoltaic Collector Options for Solar-Assisted Heating of a Residential Building in Germany
Flat plate solar thermal collectors and photovoltaic solar collectors in combination with an electrical resistance heater have been compared as an additional solar heat source of a gas burner-based heating system for a residential building in Germany. The dependency on solar collector field area and retrofitting level of the building has been analyzed in parametric studies. On the economic side, the results are in favor of the photovoltaic-based collector option, which is largely due to significant reductions of the grid-supplied electric power and the electrical household demand. On the energy efficiency side, the thermal collector-based variant requires smaller collector field areas and causes lower fossil demands for heating. The analyses have been done taking into account different primary energy factors and different cost assumptions.
Energy Costs Division and Plant Modification in a Large Research Complex: the Experience of Padova National Research Council (CNR) Area
The CNR area was built in the 1970s in Padova (Italy): many buildings hosting different Institutes are served by the central heating and cooling system and a common Medium and Low voltage supply. Costs division criteria, mainly based on the number of personnel units and the size of buildings of each Institute, were used in the past; due to current high costs of energy, these criteria have been revised and based on more objective parameters. This paper deals with the methods that have been studied to reduce thermal and cooling energy consumption, based on the operative conditions of buildings and specific characteristics of area HVAC (Heating Ventilation and Air Conditioning) plants. As a result of this optimization, some plant modifications have been evaluated and implemented. The results of new plant configuration and energy consumption are presented and discussed.
Indoor Air Quality and Thermal Comfort Assessment of Two Portuguese Secondary Schools: Main Results
The results of the field study about indoor thermal comfort in two of the involved schools of the 3Es project are presented. The thermal comfort and indoor air quality assessment was conducted by monitoring physical parameters and survey questionnaires. The subjective assessment shows that the students found temperature range beyond the comfort zone acceptable, and revealed the occupants' accommodation to CO2 exposure. The CO2 exceeding values exposed that IAQ is a problem and action should be taken to promote CO2 dilution when HVAC systems are not active.
Relationship between Thermal Environmental Acceptability and Individual Characteristics in an Office
We examine the acceptability of the thermal environment to office workers using data recorded with the Ostracon voting device. Although temporal changes in the overall indoor thermal environment were seemingly small, the spatial distribution of the thermal environment changed. Unacceptable votes in the middle of the thermal environment occurred regardless of the perimeter thermal environment, suggesting that temperature was less relevant to acceptability in the middle of the thermal environment.
Compliance with Summer Thermal Comfort Requirements in Apartment Buildings
In this study we have investigated the compliance with summer thermal comfort requirements of 16 new apartment buildings in Estonia by modelling and simulating dwellings using energy and indoor climate simulation software IDA-ICE. We also conducted field measurements of indoor temperature in 17 dwellings in 16 different apartment buildings during the period from 1 July to 31 August 2014. It has been found that 81.3% of the simulated buildings do not comply with the requirements. Measurements show that overheating can be a problem in apartment buildings also in cold climate regions.
Usage Survey of Personal Underfloor Air Outlet System and Thermal Environment Acceptability
This study was aimed to clarify the usage of a personal air-conditioning system and to describe the characteristics of actual worker acceptance of the thermal environment. The results showed that the usage rate of the personal air-conditioning system was 90% and that most workers were satisfied with the system’s effect. Only a few workers reported that the environment was unacceptable despite the use of the system, and they expressed this even when the temperature and humidity were within a comfortable range. It was suggested that the complaints resulted from factors such as the individual thermal histories and changes in their metabolic rate upon returning to the office after performing outdoor activities.
Development of Air Supply Nozzle for Stadium Chair
This paper describes the development of airconditioned seats for outdoor stadiums and reports their performance results. After considering the best location for the installation of the air supply port, the air outlet was mounted on the cup holder. Because of its concentric circular form, the outlet located in the cup holder is able to blow air upward to the occupied zone. An experimental cooling performance evaluation was conducted, which compared the proposed cup holder nozzle with standard, riser-mounted, stadium air conditioning systems.
Analysis of Indoor Air Quality in a Naturally Venti-lated University Building, Determination of an In-door Air Quality Indicator
The indoor environment is characterized by thermal comfort, indoor air quality, lighting, acoustics and others compo-nents. A pilot study was performed in order to figure out a venti-lation indicator. The study is focused on the search for the indica-tor, which can specify a minimum ventilation rate for office buildings and school buildings. How should ventilation system control perform – based on which pollutant? In the indoor air, there are many pollutants which might be subject of investiga-tion. The study continues and develops the results of Clear – up project implemented at the CTU during years 2008 – 2012. The indoor air quality is analysed and evaluated in an office building of a university based on the concentration measurements of chemical pollutants. The office building envelope has been re-cently retrofitted. The paper is focused on the question how the IAQ in an office is influenced by a natural ventilation rate and by a new retrofit-ted facade. The comparison of Czech, German and World Health Organization (WHO) standards is included. The main results are expressed by percentage frequency of the measured concentra-tions divided by permissible exposure limits (PELs). The aim of the manuscript is to find an indicator for a naturally ventilated office. The measurements were carried out in November and December 2014. The selected pollutants were measured: total volatile organic compounds TVOC, carbon dioxide and formal-dehyde. The measurements were carried out in three different standpoints. These standpoints were specially chosen in order to describe IAQ in the whole office and anticipate non-uniformity in pollutants distribution. The SF6 tracer gas was used to determine air change rate. The measurements were carried out by a photo-acoustic field gas monitor. Its measurement principle is based on the photoacoustic infrared detection method. The concentration decay method was used to determine the air change rate via nat-ural ventilation through the building envelope. The air change through building envelope was calculated according to SF6 con-centration and the air changes according to some selected pollu-tants were calculated. The boundary outdoor conditions were taken from measurements made by the Czech Hydro Meteorolog-ical Institute (CHMU) and the National Institute for Public Health (SZU) for the city of Prague location. The air change val-ues were given in a table. The manuscript showed the IAQ indi-cator. The paper shows the importance of boundary conditions (outdoor pollution conditions and indoor equipment) of the IAQ calculations and measurements. The manuscript is intended to generalize the obtained results. According to the standard [7], the ventilation rate is supposed to be 0.1 1/h. The ventilation rate through the facade and building envelope is 0.108 1/h but it is not sufficient. The sufficient ventilation rates were calculated accord-ing to different pollutants to the values 0.123 and 0.129 and 0.120. The ideal value is 0.13 1/h.
Analysis of Thermal Comfort Conditions and Actual Energy Efficiency for Different Heating Systems in Test Buildings
The aim of this study is detailed analysis of long-term monitoring data on thermal comfort conditions and energy efficiency in small test buildings equipped with different heating systems. Calculations of PPD index and local thermal discomfort factors, as well as actual energy efficiency ratios for different heat pump systems are provided for the test buildings during three weeks of the heating season. It is shown that the type of heating system has an influence not only on heating energy needs, but also on thermal comfort conditions in the room.
Case Study of Indoor Air Quality and Energy Efficiency in Passive House in Latvia
This paper presents a case study of a residential passive house in Latvia. Indoor air quality was measured during autumn and winter. The main objective of the study is to determine indoor air quality parameters in the new passive house building- air temperature, relative humidity and CO2 level. This paper will be illustrated with pictures, tables, and construction elements of the passive house.
GreenHP: Next Generation Heat Pump for Retrofitting Buildings – New Evaporator Component for Large Capacity Air-to-Water Heat Pumps
Air to water heat pumps account by more than 70% for the main share of HP-systems of the European HP market. Retrofitting applications in particular show a very high potential for the A/W heat pump technology. Innovative components will pave the way for the next generation heat pumps. In case of the evaporator, low refrigerant charge is introduced by using bionic distributors and evaporator icing is studied on several heat exchanger designs by using advanced experimental and numerical methods.
Improving Energy Efficiency of a Refrigeration System with a Rankine Cycle and an Expander
A method to increase energy efficiency of a vapor compression refrigeration system by using a Rankine cycle and an expander is studied. The systems studied include the R134a and the transcritical CO2 cycles with a 5 kW capacity. The working fluids of the Rankine cycle are R134a, propane and R123. The available heat input power is 1-5 kW. The results show that in the R134a and CO2 systems, 18-40% and 30-67% improvements of Coefficient of Performance (COP), respectively, can be achieved. The method is particularly attractive if there is abundant waste/free heat to be utilized.
Development of a Hardware-in-the-Loop Test Method for Heat Pumps and Chillers
The work presents the development of a Hardware-in-the-Loop test method which enables the solving of integrated energy design problems at a system and concept level for the heat and cold supply of NZEBs based on electrically and thermally driven heat pumps and chillers. The main result is the realization of a test rig consisting of hardware (e.g. thermally driven chiller, or heat pump etc.), of software (e.g. LabView, TRNSYS) and the interface for the interaction of hardware and software.
COP Evaluation for a Membrane Liquid Desiccant Air Conditioning System Using Four Different Heating Equipment
Liquid desiccant air conditioning (LDAC) is a promising technology in terms of energy efficiency, comfort and indoor air quality. The major components of a LDAC system are the dehumidifier and regenerator. The most commonly used design of dehumidifiers/regenerators is the packed-bed, which might result in the entrainment of desiccant droplets in air streams. A promising solution for the entrainment of desiccant droplets in air streams is to use a liquid-to-air membrane energy exchanger (LAMEE) as the dehumidifier/regenerator. A membrane LDAC system, which uses two LAMEEs as the dehumidifier and regenerator, is investigated in this paper. The operation of a LDAC system requires the continuous supply of heating and cooling energy to the desiccant solution. In this study, the COPs of four membrane LDAC systems are evaluated when four different heating equipment are used to provide the solution heating loads as follows: a gas boiler, a solar thermal system, a heating heat pump, and the condenser of a solution cooling heat pump. The COPs of the four systems studied are evaluated under wide ranges of six design/operating parameters as follows: ambient air temperature (Tamb) and humidity ratio (Wamb), number of heat transfer units (NTU), solution-to-air heat capacity ratio (Cr*), and solution inlet temperatures to dehumidifier (Tsol,deh,in) and regenerator (Tsol,reg,in). TRNSYS and CYCLE_D programs are used in this paper to simulate the performances of different systems studied. Results show that the membrane LDAC system which uses a single heat pump to provide the solution heating and
Simulation Study of a Heuristic Predictive Optimization Scheme for Grid-Reactive Heat Pump Operation
A heuristic predictive optimization scheme for gridreactive heat pump operation is introduced in this paper. It is based on thermal demand predictions (domestic hot water, heating demand) and does not require any numerical optimization which makes it easy to implement on real hardware. It follows the idea to use the heat pump to overheat the existing hot water storage in times of cheap electrical energy (oversupply). This way, converting electrical into thermal energy allows to economically shift electrical loads and hence to react at grid needs. The proposed optimization scheme is evaluated in a simulation study based on the simulation platform TRNSYS. A detailed evaluation of the algorithm in different application scenarios has been conducted by using a comprehensive system model of the investigated solar heat pump system. The evaluation presents the impact of different characteristics of the incentivizing price signal as well as prediction errors onto the load shifting and cost saving potential.
Review of Large-Scale Heat Pumps and Potential of their Introduction to Natural Gas Markets
Heat pumps are gaining popularity all over the world. A lot of attention is paid to household and commercial use markets, as well as diverse small and medium scale industrial applications. On the other hand, large-scale customized heat pumps are still more an exception in energy industry than a common practice. This paper looks into existing large-scale heat pump installations in order to gain understanding of their integration acceptance. The investigation shows that a vast majority of large-scale heat pumps use electricity as input driving energy. In many areas of the world, electric energy is comparatively expensive and therefore heat pumps are not utilized to a great extent. However, by changing the input driving energy source, large-scale heat pump systems may find acceptance in new markets. In this paper, large-scale heat pump systems which use the mechanical energy output from a natural gas fired gas turbine as input driving energy source are investigated. The output heating energy from the heat pump is used to satisfy the heating energy requirement for a city using district heating. A simplified feasibility study shows that a large reduction in primary energy consumption can be achieved with such a system compared to production of heating energy by combustion of natural gas in a boiler.
Evaluation of Exhaust Gas Condensing Economizer Installation at Riga CHP Plants
In this study, passive exhaust gas condensing economizer installation is evaluated at Riga CHP plants No. 1 and No. 2 to increase efficiency of heat only boilers (HOBs). Five options are investigated: two options for Riga CHP plant No. 1 and three options for Riga CHP plant No. 2. The study provides the analysis of HOBs operation statistics, determination of HOBs operation trends, development of production programmes, as well as economic and sensitivity analysis of the considered options. Based on economic analysis, the best option for installation of passive exhaust gas condensing economizer for Riga CHP-1 and Riga CHP-2 was chosen.
Solid Particle Emission Abatement from Biomass-Fired Boilers in District Heating Plants
Biomass combustion technologies have undergone rapid development during the last decades to become environmentally friendly. In order to evaluate the particulate matter formation and emission into the atmosphere, the measurements have been done in three wood biomass medium-scale district heating plants using different combustion technologies and various types of particle abatement equipment. The study shows similar solid particle formation in the boilers if they are operated at full load and favorable combustion conditions. The abatement units properly operated can reduce the particle emissions down to 40% from the maximum calculated limit.
Technical Studies on Development of the Dobele Underground Natural Gas Storage Facility
Dobele structure is the only large scale underground water horizon structure in Latvia, except the existing Inčukalns UGS facility, suitable for creation of UGS, where the geological surveys have ever been carried out. Since 1970s 23 wells were drilled there, the exploratory activities of different scale continued in 1990s and 2008 – 2010. The results of the geological and well condition assessment done between 2008 – 2010 within the scope of the project “Geological and Economic Research of Possible Establishment of Natural Gas Storage Reservoirs in Latvia, Dobele District” 2006–G 130/06–TREN/06/TEN–E–S07.68968 confirmed that the technical condition of a few existing ground infrastructure elements (wells) in Dobele is satisfactory, but other elements, however, can no longer be used for operational or monitoring purposes.
Heat Consumption Assessment of the Domestic Hot Water Systems in the Apartment Buildings
This study presents the analysis of energy consumption for domestic hot water in apartment buildings in Riga, Latvia. The aggregate data contains information about 39 apartment buildings, including heat energy consumption and domestic hot water (DHW) consumption. The analysis is focused on the heat energy consumption and seasonal characteristics in the DHW system. The analysis characterizes the DHW consumption, energy consumption for DHW and energy losses in the DHW systems in apartment buildings.
The Technical-Economic Analysis of Hot Water Supply Systems for Residential Buildings
The article presents the measurements of hot water and supplied thermal energy consumption in residential buildings, where alterations in bottom distribution were made. Diagrams of hot water and supplied thermal energy consumption for 1 m³ hot water preparation were constructed, using the aggregated data. The research results show that hot water consumption differs from values offered in Regulations of Building Standard LBN 221-98, but the supplied thermal energy consumption for 1 m³ hot water preparation has considerably decreased.
Low-Temperature Heating Systems Control in Low-Energy Buildings
The paper deals with the control of low-temperature heating systems and their responses to changes in indoor environment with the main focus on indoor environmental quality and real energy savings reflecting low-energy buildings energy needs. In relation to energy savings, utilization of low-temperature heating systems is increasing today, in connection with low-temperature heat sources, such as heat pumps. Lower temperature difference between the heating unit and the environment, along with the heat capacity, however, requires better control to be able to make effective response to potential changes in the indoor environment.
Optimization of Solar Cooling System in Latvia
The paper presents optimization of Solar Cooling System in Latvia using the modelling of solar cooling system which was created by dynamic simulation program. The model is similar to the existing real solar cooling system in the Institute of Physical Energetics. The precision of the model was tested by comparing it with real equipment. Simulations were carried out using metrological data of different European countries. Simulation results, dependency of heat carrier average temperature and proportion of energy from pump to the system were collected and analysed. Different element location of solar cooling system was compared in two models. Annual cool production of solar cooling system was defined.
Predesign Evaluation of St. Petersburg State Polytechnical University Campus Energy Efficiency Measures
This article describes the process and results of the first stage of work within the developed program of reconstruction of heating systems of the central platform of SPbSTU, according to the requirements of Federal Law No. 261-FZ of the Russian Federation “On energy saving and increase of energy efficiency”. Recent particular interest in energy efficiency in buildings and optimization of consumption of energy resources has determined the relevance of the work. The potential for energy saving measures has been evaluated and a concrete plan for further steps has been developed in the second stage of the work.
Energy Efficiency of Short-Term Natural Room Ventilation
A comparison of natural trickle ventilation with a constantly opened window, forming a small vent opening, versus short-term ventilation performed by a briefly wide opened window has been made using CFD. It is shown that the value of energy efficiency of the short-term ventilation can be both positive and negative depending on the intensity and frequency of its realization. The nomogram of energy efficient usage of the periodic short-term ventilation has been developed on the results of physical experiment.
Effect of Physical Treatment on the Properties of Composites Based on Natural Fibres
Due to the low density and high porosity of the hemp hurds, the combination of hemp and binder creates a building material with good thermal and acoustic insulation properties. Today hemp hurds can be used in high-quality products such as hemp concrete, fibre board and composites. In this paper, the attention is given to the study of the properties of lightweight composites based on modified hemp hurds as filler and MgO-cement as binder. The cohesion of the filler and of the binder is an important factor in the development of mechanical properties. The impact of ultrasonic treatment of hemp hurds and its cooking in water for 1h on the physical and mechanical properties (compressive strength, density, water absorbability, thermal conductivity) of the composites hardened in indoor condition was studied. The observation is also focused on the influence of the hemp hurds length. The durability of produced composites was studied under different conditions.
Cellulose Fibres Used in Building Materials
The paper presents application of cellulose fibres in a pulp form from waste paper to mortar or plaster. The pulp from waste paper substitutes a part of inorganic filler or binder in cementitious composites. The characterization of properties and use of mortar or plaster mixtures as well as wood pulp fibres used in cement-based materials is presented in the article. The results of testing the technically important parameters (density, water resistance, coefficient of thermal conductivity, tensile strength at bending) of composites which were obtained by compiling the available works are summarized.
Air Heating Solar Collector for Hemp Drying
Attempts to use solar energy for drying of hemp (and other agricultural production) have been made in this work. Air is heated in solar collector approximately to 40 – 60 degrees Celsius, which also results in decreasing of the humidity of this air from 60 % (normal ambient air humidity) to 18 - 8 % respectively. Then such hot dry air is used for drying of hemp or other agricultural production. A new construction of air heating solar collector – a cylindrical solar collector has been worked out.
Structurally-Oriented Design of the Heat Insulation Plastering Material
Theoretical foundations and the results of preliminary experimental studies related to the design of the heat insulation plastering material are considered. The main problem is to provide heat-insulating properties and strength characteristics of the appropriate level required. The solution is based on the percolation theory, allowing to determine the proportion of thermal insulating filler to interrupt most of thermal paths, and ideas of structural optimization, allowing to increase the strength of the material due to the selection of particle size of the basic components - gypsum and perlite powder, as well as by the introduction of mineral and organic additives. Methodological techniques developed in the implementation of these directions are applicable for other tasks of building materials science.
There should be a balance between artificial environment and natural environment. As forests, fields, gardens and urban lands are being replaced with bituminous, concrete and unnatural surfaces, necessity of recovering green and blue spaces and natural areas is becoming more and more critical. Green roof is a tool in strategy of making more pervious areas and beating more impervious areas. Green roof is lately becoming part of urban storm water management. Considering this fact, new construction solutions help green roofs become blue roofs. Typical green roof is becoming an increasingly popular solution of impervious roof top of the building. New construction solutions with temporary water reservoirs help the original green roof become retention blue roof. Storm water management should enable the natural processes to infiltrate, evapo-transpire or capture and use storm water on or near the site, potentially generating other environmental benefits. The water cycle should be managed to close the loop, although this is not always possible. Rainwater needs to be harvested and recycled. Surface water needs to be retained within the site and returned to the land for the recharging of groundwater by means of filtration beds, pervious roadways and built surfaces, retention ponds and bio-swales. Water used in the built environment needs to be recovered and reused wherever possible. The aim of this article is to lay out technical specifications of different green roofs in terms of water retention, discharge coefficient and water storage. In this article, different roofs with vegetation on the top of the roofs are described. Diverse roof layers creating diverse roof constructions have different features. Capability of different roofs for catching rainwater, reducing pollutants, compared to typical water runoff, entering watershed and keeping liters out of the city sewer system are one of the main goals of this article. Novelty in co-operation of landscape and dwelling is bringing nature to the city, making green and blue fashionable, making green-blue roof fifth living facade of the building, designing healthy and vegetated towns. Very old method of improving sustainability is introducing green and blue key elements in the environmental strategy.
Urban Development of Tirana after 90 years and its Environmental Problems
The developments in the last two decades in Albania after the fall of communism are associated with major changes, both socio-economic and environmental. In the context of environmental change, Albania is one of the remaining countries with a wide range of problems that have constantly been in the focus of attention of not only the state institutions but also of the non-governmental organizations, which are operating in our country. Tirana is a city that is considering and dealing with its environmental problems. Tirana as the capital of the country has experienced such an extra ordinary transformation in more than two decades that has not been without its environmental costs. Human activities have transformed the environment in Tirana. Greater quantities of waste generated, especially of solid waste, are caused by the major construction boom. Considerable amount of clinical waste is disposed in urban waste in the places where hospitals and clinics are situated. Tirana’s clinical waste is burned in special places. As the economy of the city grows, this volume will increase. In this context, our paper will focus on a more extensive treatment of these problems, providing forecasts for the future as well as considering the measures to reduce the negative aspects of urban development to the levels required by the EU.
The Impact of Authorized Representatives on Energy Efficiency in Multifamily Apartment Houses and Prolongation of the Lifetime of the Buildings
It has been determined that apartments are the most common type of immovable property owned by the inhabitants of Latvia. The detailed analysis of the housing stock of the country shows that the lifetimes of numerous residential buildings are overestimated and only proper administration and maintenance might prolong the terms. The election of authorized or delegated representatives in intercommunities definitely leads to the increase of energy efficiency of the house and ensures proper management of other everyday occasions.
Evaluation of the Impact of the Additional Mass of an Innovative AC System on the Overall Energy Consumption of a Battery Electric Vehicle in Tropical Climate
One of the major issues concerning the inclusion of additional components in vehicle for its efficiency improvement is the increase in mass of the vehicle. The increased mass causes an increased energy demand for propulsion of the vehicle. This paper aims at analyzing the impact of the added mass of an innovative air conditioning system powered by bio-ethanol based auxiliary power unit on the overall energy use of electric vehicles that are designed for the tropical climate of Singapore.
20 % Reduction of CO2-Emissions with Power-to-Gas in WWTP
The engineering company Witteveen+Bos and the Water Board Aa en Maas explored the potential of a new concept combining Power-to-Gas (PtG) and sludge digestion in Wastewater Treatment Plant (WWTP) Cuijck. This project aims to tackle two topical issues at once, which are respectively the need for increase of energy storage for renewable energy production and the need for reduction of greenhouse gas emissions. The main conclusion of this study shows that Powerto- Gas systems can reduce around 20 % of the carbon dioxide (CO2) emissions and provide long term storage of 126.5 MWh/year (140 579 Nm3 Synthetic Natural Gas/year) at the WWTP of Land van Cuijk.
Influence of Silica Fume on Durability of Cement-Based Materials Exposed to Chlorides
The deterioration of cement-based materials used for the civil infrastructure has led to the realization that cement-based materials, such as concrete, must be improved in terms of their properties and durability. The use of admixtures, e.g. silica fume, is a relatively convenient way of improving cement-based materials. This paper is focused on the use of silica fume to improve durability of cement-based materials exposed to hydrochloric acid. Effect of hydrochloric acid attack on the silica fume based cement composites and cement composites of ordinary CEM I Portland cement without any additives was investigated during 180 days under model laboratory conditions. The calcium and silicon contents in leachates were evaluated during the experiments using X – ray fluorescence method (XRF). Silica fume based concrete samples were found to have better performance in terms of calcium and silicon ions leaching for all environments except for distilled water environment. The highest concentrations of leached calcium (619.2 mg/L) and silicon (1581 mg/L) ions were observed for the sample without silica fume addition placed in the solution of hydrochloric acid.
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