State of the Art on Heat Pumps for Residential Buildings

Heat Pumps are becoming one of the most considered mechanical conditioning equipment in our buildings. While they are popular, there appears to be quite a vast range of system types and applications in building conditioning. This paper primarily reviews the literature on heat pumps, the various types, and the consideration of design end uses. The fact that there are different energy sources for heat pumps is considered, as well as the different sinks in which energy is stored or dissipated. It is evident that advanced heat pump systems cater well to the use of renewable energy resources. Therefore, in the move towards net-zero energy building operation, the correct selection of a heat pump can help to increase self-consumption of solar PV generation and even make use of direct solar energy heating. This paper reviews the technologies for heat pump selection, application, and design for residential buildings.

Evaluation of the Thermal Performance and Energy Efficiency of CRAC Equipment through Mathematical Modeling Using a New Index COP WEUED

As the world data traffic increasingly grows, the need for computer room air conditioning (CRAC)-type equipment grows proportionally. The air conditioning equipment is responsible for approximately 38% of the energy consumption of data centers. The energy efficiency of these pieces of equipment is compared according to the Energy Standard ASHRAE 90.1-2019, using the index Net Sensible Coefficient Of Performance (NetSCOP). This method benefits fixed-speed compressor equipment with a constant inlet temperature air-cooled condenser (35 °C). A new method, COP WEUED (COP–world energy usage effectiveness design), is proposed based on the IPLV (integrated part load value) methodology. The IPLV is an index focused on partial thermal loads and outdoor temperature data variation for air intake in the condenser. It is based on the average temperatures of the USA’s 29 major cities. The new method is based on the 29 largest cities worldwide and with data-center-specific indoor temperature conditions. For the same inverter compressor, efficiencies of 4.03 and 4.92 kW/kW were obtained, using ASHRAE 90.1-2019 and the proposed method, respectively. This difference of almost 20% between methods is justified because, during less than 5% of the annual hours, the inlet air temperature in the condenser is close to the NetSCOP indication.

Risk Assessment of a MLCC Plant through Fire and Evacuation Simulations

In this paper, fire and evacuation simulations are conducted for the Multi-Layer Ceramic Capacitor (MLCC) factory clean room, and a plan to improve performance standards in the field of performance-based design simulation is suggested. First of all, fire and evacuation risk factors in the clean room were derived through fire accidents and previous research. And fire and evacuation simulations were performed using the derived risk factors as variables. As a result of the simulations, it was found that 'air conditioning equipment', 'working capacity', 'door setting method' and 'life safety evaluation method' have an influence on the life safety evaluation. Finally, a plan to improve the standards for fire and evacuation simulation was suggested to reflect the factors influencing the life safety evaluation.

Impacts of Air Conditioning Equipment Sizing on Energy Performance of US Office Buildings

The paper summarizes the results of a systematic and comprehensive analysis to investigate the impacts of inadequate sizing air conditioning (AC) systems on the overall energy consumption of medium and large office buildings located in representative US cities. The effects of proper sizing on the overall and disaggregated AC systems are evaluated in terms of energy consumption, peak demand, equipment run-time, and indoor thermal comfort. The presented analysis covers the performance a wide range of AC equipment components that serve US office buildings including packaged rooftop units as well as central cooling plants. The analysis results indicate that oversizing penalties can be significant on the annual energy consumption and electrical peak demand as well as capital costs for both medium and large office buildings. In particular, the reliance on simplified calculation methods and rules-of-thumb to determine equipment capacities can lead to significantly oversizing AC systems for office buildings in the vast majority of US climates and can result in increases of annual energy consumption and electrical peak demand of up to 29%. Moreover, oversizing increases capital costs required for air conditioning office buildings and extends cycling periods and associated structural stresses and failures of AC equipment.

Optimal Building Thermal Load Scheduling for Simultaneous Participation in Energy and Frequency Regulation Markets

This paper presents an optimal scheduling solution for building thermal loads that simultaneously participate in the wholesale energy and frequency regulation markets. The solution combines (1) a lower-level regulation capacity reset strategy that identifies the available regulation capacity for each hour, and (2) an upper-level zone temperature scheduling algorithm to find the optimal load trajectory with a minimum net electricity cost. In the supervisory scheduling strategy, piece-wise linear approximations of representative air-conditioning equipment behaviors, derived from an offline analysis of the capacity reset mechanism, are used to predict the cooling power and regulation capacity; and a mixed-integer convex program is formulated and solved to determine the optimal control actions. In order to evaluate the performance of the developed control solution, two baseline strategies are considered, one with a conventional night setup/back control and the other utilizing an optimization procedure for minimizing the energy cost only. Five-day simulation tests were carried out for the various control strategies. Compared to the baseline night setup/back strategy, the energy-priority controller led to a 26% lower regulation credit and consequentially caused a net cost increase of 2%; the proposed bi-market control solution was able to increase the regulation credit by 118% and reduce the net electricity cost by 14%.

Towards Zero Energy Districts developments base on bioclimatic strategies: A Numerical Study in a Developing Country

The need for more efficient buildings to contribute to more sustainable development has led to the establishment of targets in different countries. European countries have presented energy plans to respond to the guidelines of achieving near-zero energy buildings (nZEB). The concept can be defined at the urban scale (nZED), being a delimited part of a city with high energy efficiency and using renewable energies within its boundaries. This research aims to carry out a numerical study in a residential development in Panama, based on a proposal to redesign it, but using bioclimatic strategies and implementing photovoltaic technology. Thus, to evaluate the feasibility of nZED in the region and to function as a preliminary study to implement regulations of this type in the country. The results indicate that the indoor comfort conditions of each residential building should be evaluated in greater depth, and energy savings of 40% were obtained by implementing the recommended bioclimatic strategies and becoming independent of air conditioning equipment. In addition, photovoltaic generation outstrips demand, making the development net energy positive.