Maria Justo Alonso

• Doctor of Engineering
• Senior Researcher at SINTEF

Efforts to enhance the energy efficiency of heating, ventilation, and air conditioning (HVAC) systems have been bolstered by technical advancements and stringent regulations. However, HVAC systems not only emit during operation due to energy consumption but also have significant embodied emissions, which recent studies show can exceed those of the...

Membrane energy exchangers (MEEs) are increasingly being studied and utilized to contribute to realising energy-efficient building services and providing satisfactory indoor environments. The performance of MEEs has been extensively studied in terms of heat and mass transfer and pressure drop (PD). However, a model for optimizing the performance of...

Energy-efficient building services are necessary to realise zero-emission buildings while maintaining adequate indoor environmental quality. As the share of ventilation heating needs grow in well-insulated and airtight buildings, heat recovery in mechanical ventilation systems is increasingly common. Ventilation heat recovery is one of the most eff...

Providing a high-quality indoor environment with appropriate indoor humidity levels for residential buildings is essential for good physical and mental health, occupant comfort, and long-term building performance. The role of moisture recovery in indoor humidity levels in cold climates has long been the subject of controversy; scholars have debated...

Ventilation control logics are usually based on the control indicators of occupancy. However, strategies including control of contaminants not linked to occupancy are requested and more feasible with the introduction in the market of low-cost sensors (LCS). In this work, a methodology for the improvement of demand-controlled ventilation (DCV) using...

Xylem in Emmaboda, Sweden, has one of the first borehole thermal energy storage (BTES) sites storing excess heat and has been previously thoroughly studied and monitored. Here, the results from distributed temperature sensing (DTS) measurements in observation boreholes, UB1, 10 m outside the BTES, and UB46, inside the BTES, are presented. The measu...

In this study, concentrations of pollutants: formaldehyde, carbon dioxide (CO2), and total volatile organic compounds (TVOC) and parameters: indoor room temperature and relative humidity (RH) were measured in 21 home offices for at least one week in winter in Trondheim, Norway. Eleven of these were measured again for the same duration in summer. Po...

Today's buildings are becoming more insulated and airtight to reduce transmission heat losses. Energy use for ventilation can represent up to half of these buildings' total energy use. Heat recovery in ventilation and demand-controlled ventilation (DCV) are energy-efficient measures to reduce ventilation energy use, especially when combined. Howeve...

Membrane energy exchanger (MEE) for a new generation of energy efficient heating, ventilation and air conditioning (HVAC) systems has attracted wide attention. As MEE has been increasingly employed, extensive studies of heat and moisture transfer features have been carried out. Nevertheless, odour transfer through MEE, which may cause odour nuisanc...

To achieve energy efficiency and lower carbon emissions, building envelopes have become tighter and more insulated. These buildings must have mechanical ventilation with high efficient heat recovery to provide adequate indoor air quality using low energy in cold climates, and requirements for heat recovery efficiency are expected to increase. Today...

This study reviewed heat recovery technologies and their application in residential buildings in cold climates. The increasing efforts on reducing building energy use over the recent years have resulted in improved insulated and airtight buildings. Reduced infiltration can result in poor indoor air quality owing to insufficient ventilation rates. I...

Low-cost sensors (LCS) are becoming ubiquitous in the market; however, calibration is needed before reliable use. An evaluation of the calibration of eight identical pre-calibrated formaldehyde LCS is presented here. The LCS and a reference instrument were exposed to a pollutant source(s) for the calibration measurements. After one year, some tests...

Balanced mechanical ventilation equipped with heat recovery has been widely adopted in cold climates to ensure an acceptable indoor environment in energy-efficient buildings. An acknowledged trend to achieve more energy savings is to increase the temperature efficiency of heat recovery. As one of the efficient heat recovery technologies extensively...

CO2 is customarily used to control ventilation as it is a proxy for bio-effluents and pollutants related to the presence and activity of people in the room. However, CO2 could not be a satisfactory indicator for pollutants that do not have a metabolic origin, i.e., emissions from building materials or emissions from traffic. A methodology to select...

A coupled energy, airflow, and contaminant transport building model was developed using co-simulation between EnergyPlus and CONTAM. The model was used to analyze different strategies to control supply air delivery and return air recirculation rates including the use of demand-controlled ventilation (DCV) strategies. Strategies were evaluated for t...

In 2020, due to the outbreak of COVID-19 many workers have been sent home to avoid the sickness spread. As a result, rooms that otherwise had domestic use, living rooms or bedrooms, have become offices. This change has happened in many houses without improving the ventilation systems. In many cases, the rooms were overcrowded, and no attention was...

Geothermal energy use has increased in popularity in Norway. The total estimate of direct use of geothermal energy in Norway is 3.0 TWh. This represents 30 % growth since the 2015 WGC report. The majority of geothermal energy systems are geothermal heat pump (GHP) installations extracting or storing heat by BHEs in crystalline rocks. Single U-pipe...

The purpose of this chapter is to present the basic features of air-handling processes, relevant technologies and equipment. This chapter aims to provide links between the basic theories of air-handling processes and the actual equipment, including air filters, heat exchangers, and fans. This revised chapter deals with the basic air-handling proces...

This work presents a novel occupancy simulation model for residential buildings. The main contribution is that occupancy is simulated at room level, as opposed to more course spatial resolutions in previous studies. The model is based on a time-use survey conducted in Denmark including several thousand households. It is formulated as an inhomogeneo...

Heat recovery in ventilation is essential to reduce energy use and thus mitigate greenhouse gas emissions from the building sector. Heat recovery efficiency of at least 80 % in new buildings is required according to Norwegian standards. However, measurements show that the real heat recovery efficiency during operation is commonly 10-20 % lower. Mea...

2020Park is an innovative installation in Stavanger, Norway. This installation provides heating and cooling via a ground source heat pump (GSHP). The system combines eight 220m deep boreholes, with an air to brine heat exchanger and the heat from cooling 15 square meters of thermal photovoltaic cells (PVT). The GSHP has a rated coefficient of perfo...

A data set of heat load measurements for 197 buildings from different building categories (apartment blocks, hotels, nursing homes, offices and schools), have been analysed to evaluate the potential for peak shaving. A moving average filter is applied to investigate how smoothening of the load profiles can reduce the peak loads. It is shown that fo...

This work presents a novel occupancy simulation model for residential buildings. The main contribution is that occupancy is simulated at room level, as opposed to more course spatial resolutions in previous studies. The model is based on a time-use survey conducted in Denmark including several thousand households. It is formulated as an inhomogeneo...

This work presents a novel occupancy simulation model for residential buildings. The main contribution is that occupancy is simulated at room level, as opposed to more course spatial resolutions in previous studies. The model is based on a time-use survey conducted in Denmark including several thousand households. It is formulated as an inhomogeneo...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building's real demand offers large potential for energy savings over the status quo. Building occupants' presence as well as mechanically supplied and infiltrated airflow r...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building's real demand offers large potential for energy savings over the status quo. Building occupants' presence as well as mechanically supplied and infiltrated airflow r...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building's real demand offers large potential for energy savings over the status quo. Building occupants' presence as well as mechanically supplied and infiltrated airflow r...

High temperature district heating systems are connected to high losses, therefore, new district heating systems have lower temperatures. In Zero Emission Neighborhoods (ZEN) the heat demands are reduced and 4th generation district heating (4DH) solutions opens as a solution to provide the heating demands with lower transmission losses. However, dis...

In the existing building stock, heating, cooling and ventilation often run on fixed schedules assuming maximal occupancy. However, fitting the control of the HVAC system to the building’s real demand offers large potential for energy savings over the status quo. Building occupants’ presence as well as mechanically supplied and infiltrated airflow r...

The IEA HPT Annex 49 "Design and integration of heat pumps for Nearly Zero Energy Buildings" deals with the design and integration of heat pumps as core component of the HVAC system for Nearly or Net Zero energy buildings (NZEB). The IEA HPT Annex 49 has been structured into four tasks which comprise the following investigations: Task 1: State-of...

Zero emission buildings (ZEB) are characterized by high levels of insulation and air tightness. Powerhouse Kjørbo is the first Zero Emission Renovated Office Building in Norway. In 2013-2014 the building from 1985 underwent a major renovation to passive house standard (class A), keeping only the concrete framework to reduce emissions. The building...

The necessity to drastically reduce the space-heating (SH) needs of residential buildings in Europe has pushed the emergence of building concepts based on a super-insulated building envelope, such as the passive house (PH) standard. In these envelopes, the SH distribution system can be simplified because it is theoretically not necessary anymore to...

In the development towards nearly zero energy buildings (nZEB) the load profiles for the heat demand and the heat use of the buildings are expected to be changed considerably compared to the situation today. This change will influence the design and the overall profitability of district heating (DH). Earlier heat use measurements have shown that th...

The present study investigates effects of longitudinal heat conduction (LHC) on the heat recovery effectiveness of the heat wheel in the Powerhouse building “Kjørbo”. The effects LHC which are usually ignored in the heat wheel design play a relatively significant role in the heat wheel with high temperature efficiency and short depth in flow direct...

Membrane energy exchangers (MEEs) can reduce or avoid frosting in cold climates since the moisture transfer lowers the dew point of the exhaust air and as a result, the exchanger can be frost-free at lower outdoor air temperatures or higher indoor humidities. A frosting limit is necessary to predict at which conditions the onset of frost occurs for...

With the goal of increasing heat storage in the same accumulation volumes, phase-change materials are considered. There are different substances with different phase-change temperatures that can be used for storing heating or cooling implemented in heat pump systems for applications of space heating and cooling, ventilation or domestic hot water pr...

Frosting occurring inside heat exchangers degrades the exchangers’ performance and reduces energy recovery in cold climates. The moisture transport in membrane energy exchangers (MEE) provides a great potential to increase frost tolerance and decrease energy consumption by the air handling units (AHU). In addition, the moisture recovery in MEEs ten...

The necessity to drastically reduce the space-heating (SH) needs of residential buildings in Europe has prompted the emergence of building concepts based on a super-insulated building envelope, such as the passive house (PH) standard. In these envelopes, the SH distribution system can be simplified because it is theoretically not necessary anymore...

The objective of this paper is to evaluate the indoor air quality in a renovated zero emission office building. Zero emission buildings should replace fossil fuels with renewable clean energy so that the saved emissions equals the emissions caused by the building’s construction, operation and materials. The building energy use has to be minimiz...

Efficient energy recovery from used air with the goal of reducing energy use is important for realizing low energy houses. Rotary heat exchangers are very energy efficient, but have the drawback of transferring odours from exhaust air to fresh supply air. To avoid this, flat plate heat exchangers are commonly used where odour transfer might cause p...

One of the downsides of super insulated building envelopes is their facility to be overheated needing removal of excess heat. The removal of surplus heat is often done by mechanical cooling. However, energy consumption related to mechanical cooling is incompatible with achieving zero energy buildings.

Batch freezing tunnels are essential in the cold chain for the Norwegian pelagic industry. The temperature of the fish core should be at least -18 °C before the tunnel is unloaded. In order to keep an adequate working schedule, unloading should be done within 24 hours. The construction of the tunnel and the arrangement of the products are vital for...

Realisation of Zero Energy Buildings (ZEB) for residential use cannot succeed without: minimising leakages, increasing thermal insulation and using reliable and energy efficient system solutions. However, very airtight houses may have a negative impact on thermal comfort and indoor air quality. Focussing on ventilation systems then becomes a requir...

In Norway, a large portion of the building stock originates from the period from 1955 to 1990. Many of these buildings fail to comply with the current building regulations regarding the energy consumption. In this study, the possibility for upgrading a hypothetical apartment building with an oil-based heating system has been investigated employing...

In Norway, a large proportion of school building stock originates from the period 1955 to 1987. Many of these buildings fail to comply with current building regulations concerning energy consumption, efficient ventilation and indoor air quality promoting the pupils well-being and learning. For the municipalities responsible for operation and mainte...

The requirements for conventional heat/energy recovery ventilator (ERV) mainly consider sensible effectiveness to guarantee the designed high heat recovery rate. However, a high sensible effectiveness probably leads to frost formation in ERVs in cold climates. Membrane-based energy exchangers (MEE) have a promising future as they can be designed to...

In Norway, a large proportion of school building stock originates from the period 1955 to 1987. Many of these buildings fail to comply with current building regulations concerning energy consumption. An excessive amount of energy is consumed, ventilation is unsatisfactory, and the resulting air quality and thermal climate have a negative impact on...

Reduced energy consumption is one of the most cost effective ways of reducing CO2 emissions for combustion of fossil fuels. Residential buildings must become more energy efficient according to the Energy Performance in Buildings Directive (EPBD). The demands for domestic hot water have become more significant. Therefore the share of domestic hot wa...

http://zeb.no/index.php/reports/item/406-state-of-the-art-analysis-of-nearly-zero-energy-buildings-country-report-iea-hpp-annex-40-task-1-norway

The objective of this project has been to develop a universal, well documented and transparent method and calculation tool to determine the renewable and non-renewable Primary Energy Factors (PEF) and the greenhouse gas (GHG) emissions factors for district heating and cooling (DHC) including combined heat and power (CHP). The tool has been tested...

Realization of Net Zero Energy Buildings (NZEB) for residential use depends on, among other things, minimizing leakages. However, very airtight houses may have a negative impact on indoor air quality, indoor humidity and thermal comfort. Focusing on ventilation systems becomes a requirement in this situation. In cold climates mechanical ventilation...

In a freezing tunnel, food products are cooled and frozen by cold circulating air. The products give off heat to the air, which is cooled down again in an air cooler. Refrigeration systems with freezing tunnels consume considerable amounts of energy and improvements in the tunnel design may reduce energy use. The necessary freezing time for product...