energy

A heat recovery ventilator (HRV) is used to create a balanced ventilation system in residential buildings and as an energy-saving measure. HRVs bring in outside air which is tempered with outgoing stale air, with only the small energy penalty of the blower power to overcome the pressure drop in the HRV. HRVs have been used in cold climates and have often performed poorly due to frosting failure.

This research investigates the significance of the moisture buffering and latent heat capacities in exposed cross-laminated timber (CLT) walls with the respect to indoor climate and energy consumption. Hygroscopic materials have the ability to accumulate and release moisture due to change in the surrounding humidity. The moisture buffer capacity is regarded as this ability to moderate, or buffer, the indoor humidity variations. Latent heat refers to the heat of sorption due to the phase change from vapour to bound water in the material and the other way around.

Most existing non-residential buildings have Constant Air Volume (CAV) ventilation leading to over-ventilation in periods with low or no occupancy. Demand controlled ventilation (DCV) can considerably reduce the ventilation airflow rate and energy use for fans, heating and cooling compared to constant air volume (CAV) ventilation. There is a potentially enormous upcoming marked for converting from CAV to efficient DCV in existing commercial buildings.

The purpose of this paper is to find the efficiency of window shades regarding building energy performance and explore the possibility of developing a model that enables users to find proper shades for their specific conditions. The paper investigates different options of shades and their related variables and finds the efficiency of the shades regarding energy load. Each variable was investigated for its effect on the heat loads. Results were used as input variables for neural network prediction model.  A prediction model was developed and trained based on the previous simulation results.

This paper presents the development and implementation of an Energy-based Decision Support System (EDSS) that will enhance the selection process of replacement building features. EDSS includes dynamic databases that utilize data/web mining concepts, Knowledge Base System (KBS) and a thermal simulation engine. The system allows decisions to be made based on a long-term vision incorporating energy cost savings rather than immediate needs. A stand-alone application was implemented based on EDSS.

This paper presents a set of solutions to enable  differential time scales for dynamic boundary conditions within whole-building energy simulation, specifically occupant behavioral adaptations in response to short-term changes in solar and daylighting conditions. The concept is to allow specialized libraries to determine in tandem the state of critical variables, such as window blinds and lighting systems, at higher frequencies than the building domain time step (e.g.

As strategies for improving building envelope and HVAC equipment efficiencies are increasingly required to reduce building energy use, a greater percentage of energy loss will occur through building envelope leakage. Although the energy impacts of unintended infiltration on a building's energy use can be significant, current energy simulation software and design methods are generally not able to accurately account for envelope infiltration and the impacts of improved airtightness.

Fuel cells are highly efficient energy conversion systems that have recently gained significant interest in terms of both science and applications. Exergy analysis is adopted here for a power plant involving SOFC with external steam reforming that is fuelled by modeled biogas/steam mixtures. The electrical efficiency has been estimated and the effect of various operational parameters on the process efficiency has been investigated.

The importance of adventitious air leakage under normal operational conditions and its reduction in order to save energy is highlighted by the relvant building standards of many countries. This operational leakage is often inferred via the measurement of air permeability, a physical property of a building that indicates the resistance of its fabric to airflow. A building’s permeability is the measure of airflow rate through its envelope at a constant pressure differential of 50 Pascals.

Hybrid ventilation (HV), as a combination of automated natural ventilation (NV) and balanced mechanical ventilation (MV), provides opportunities to use the advantages of both ventilation systems during the seasons in order to reduce energy demand and at the same time obtain comfortable indoor climate.