scholarly journals Enhancing energy efficiency in supermarket refrigeration systems through a robust energy performance indicator

2016 ◽  
Vol 64 ◽  
pp. 40-50 ◽  
Author(s):  
Salvador Acha ◽  
Yujia Du ◽  
Nilay Shah
2021 ◽  
Vol 246 ◽  
pp. 05004
Author(s):  
Triinu Bergmann ◽  
Aime Ruus ◽  
Kristo Kalbe ◽  
Mihkel Kiviste ◽  
Jiri Tintera

The Energy Performance of Buildings Directive (EPBD) of the EU states that Each Member State shall establish a long-term renovation strategy to support the renovation of building stock into a highly energy efficient and decarbonised building stock by 2050. The motive for the study was the dissatisfaction of inhabitants of a single-family building about the heating costs and thermal discomfort. In this study both the emotional and resource efficiency aspects were considered. The structures and technical systems of the studied small dwelling are typical of representing single-family buildings of the Estonian building stock. The initial purpose was to improve the energy efficiency of a building while preserving the existing load bearing structures as much as possible. The research questions were: 1) what the situation before the renovation was, 2) what solutions can be used, 3) making decisions, whether to renovate or demolish. Calculations were carried out – the thermal transmittance of the envelope structures was calculated based on the construction information, and the linear thermal transmittance of geometrical thermal bridges was calculated by using the software Therm. Field tests performed - the thermography and the air leakage of the building was found by standard blower-door test. Specific air leakage rate qE50=11.1 m3/(hm2) was estimated. A renovation solution was offered considering the need for extra insulation and airtightness. The dwelling energy performance indicator was reduced from the existing 279 kWh/(m2y) to 136 kWh/(m2y). For significant energy efficiency improvement deep renovation measures must be used and the question was whether it is rational. Before making the final decision, several aspects have to be considered: 1) emotional – the demolition or renovation of somebody’s home, 2) environmental aspects and resource-efficiency – the possibilities of the reuse of materials.


2017 ◽  
Vol 54 (4) ◽  
pp. 3-14
Author(s):  
I. Pukite ◽  
A. Grekis ◽  
I. Geipele ◽  
N. Zeltins

Abstract In March 2016, the Latvian government approved a new support program for increasing energy efficiency in residential apartment buildings. For the support of renovation of apartment buildings in the period from 2016 to 2023, 166 470 588 EUR will be available. Different persons, such as energy auditors, designers, architects, project managers and builders, will be involved in the process of planning, development and implementation of building renovation. At the development stage of the building renovation project, special attention should be devoted to the first stage – energy audit and technical project development. The problem arises due to the fact that each of these individuals, during the development of technical building documentation, does not work as a completely unified system. The implementation of construction project planning and organisational management system is one of the most important factors to guarantee that the quality of building renovation project is ensured in accordance with the laws and regulatory standards. The paper studies mutual cooperation, professionalism and the role of information feedback of personnel involved in the planning stage of building renovation, which is an essential prerequisite for the renovation process in order to achieve high quality of work and reduce the energy performance indicator. The present research includes the analysis of different technical solutions and their impact on energy efficiency. Mutual harmonisation of technical specifications is also investigated.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3570
Author(s):  
Endrik Arumägi ◽  
Targo Kalamees

The current study demonstrates the possibilities of reducing energy use and construction costs and provides evidence that wooden nearly-zero-energy buildings (nZEB) are technically possible at affordable construction costs by using novel design processes and procurement models that enable scalable and modular production. The energy efficiency solutions were derived by increasing/decreasing the insulation value of the building envelope in successive steps. Financial calculations were based on the investment needed to achieve the nearly-zero-energy levels. Overall, many opportunities exist to decrease the cost and energy use compared to the current (pre-nZEB) practice because the net present value can change up to 150 €/m² on the same energy performance indicator (EPI) level. The EPI in the cost-even range was reached by combining a ground-source heat pump (between 115 and 128 kWh/(m2·a)) and efficient district heating (between 106 and 124 kWh/(m2·a)). As energy efficiency decreases, improving energy efficiency becomes more expensive by insulation measures. Throughout the EPI range the most cost efficient was investment in the improvement of the thermal transmittance of windows (3–13 €/(kWh/(m2·a))) while investments in other building envelope parts were less effective (4–80 €/(kWh/(m2·a))). If these were possible to install, photovoltaic (PV) panels installed to the roof would be the cheapest solution to improve the energy performance. Integrated project delivery procurement (design and construction together) and the use of prefabricated wooden structures reduced the constructing cost by half (from ~2700 €/net m2 to 1390 €/net m2) and helped to keep the budget within limits.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3311
Author(s):  
Víctor Pérez-Andreu ◽  
Carolina Aparicio-Fernández ◽  
José-Luis Vivancos ◽  
Javier Cárcel-Carrasco

The number of buildings renovated following the introduction of European energy-efficiency policy represents a small number of buildings in Spain. So, the main Spanish building stock needs an urgent energy renovation. Using passive strategies is essential, and thermal characterization and predictive tests of the energy-efficiency improvements achieving acceptable levels of comfort for their users are urgently necessary. This study analyzes the energy performance and thermal comfort of the users in a typical Mediterranean dwelling house. A transient simulation has been used to acquire the scope of Spanish standards for its energy rehabilitation, taking into account standard comfort conditions. The work is based on thermal monitoring of the building and a numerical validated model developed in TRNSYS. Energy demands for different models have been calculated considering different passive constructive measures combined with real wind site conditions and the behavior of users related to natural ventilation. This methodology has given us the necessary information to decide the best solution in relation to energy demand and facility of implementation. The thermal comfort for different models is not directly related to energy demand and has allowed checking when and where the measures need to be done.


2020 ◽  
Vol 13 (1) ◽  
pp. 235
Author(s):  
Fernando Martín-Consuegra ◽  
Fernando de Frutos ◽  
Ignacio Oteiza ◽  
Carmen Alonso ◽  
Borja Frutos

This study quantified the improvement in energy efficiency following passive renovation of the thermal envelope in highly inefficient residential complexes on the outskirts of the city of Madrid. A case study was conducted of a single-family terrace housing, representative of the smallest size subsidized dwellings built in Spain for workers in the nineteen fifties and sixties. Two units of similar characteristics, one in its original state and the other renovated, were analyzed in detail against their urban setting with an experimental method proposed hereunder for simplified, minimal monitoring. The dwellings were compared on the grounds of indoor environment quality parameters recorded over a period covering both winter and summer months. That information was supplemented with an analysis of the energy consumption metered. The result was a low-cost, reasonably accurate measure of the improvements gained in the renovated unit. The monitoring output data were entered in a theoretical energy efficiency model for the entire neighborhood to obtain an estimate of the potential for energy savings if the entire urban complex were renovated.


2021 ◽  
Vol 13 (13) ◽  
pp. 7359
Author(s):  
Sadaf Alam ◽  
Miimu Airaksinen ◽  
Risto Lahdelma

Key stakeholders in industry are highly responsible for achieving energy performance targets. Particularly, this paper assesses the attitudes, approaches, and experiences of Finnish construction professionals regarding energy-efficient buildings, or nZEBs. A three-tier investigation was conducted including surveys and expert interviews with several stakeholders. The structure of this approach was informed by preliminary data and information available on the Finnish construction sector. The questionnaire showed that the stakeholders ranked energy efficiency and embodied energy/carbon as very important. The survey highlighted that the importance of the embodied carbon CO2 in the materials is less important than the energy efficiency from many of the stakeholders’ points of view. “Energy efficiency” is very important for ESCOs, contractors, and facility managers followed by architects, HVAC engineers, and construction design engineers. Nevertheless, the opinions of architects ranked “embodied energy CO2” as the most important regarding nZEB. When it comes to the importance of “running time emissions” toward nZEB, contractors and ESCO companies ranked it as 1 for importance followed by property owners (78%) and tenants (75%). It is very fascinating to see from the survey that “running time carbon emissions” has been ranked 1 (very important) by all stakeholders. This study will enable construction industry stakeholders to make provisions for overcoming the barriers, gaps, and challenges identified in the practices of the nZEB projects. It will also inform the formulation of policies that drive retrofit uptake.


Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 224
Author(s):  
Lucia Cattani ◽  
Anna Magrini ◽  
Paolo Cattani

Water extraction from air, based on reverse cycle systems, is becoming a technology more and more diffused and various models of air to water generators (AWG) are now available, all claiming the best efficiency. To date, there is not a standard indicator stating energy efficiency for AWGs, neither in the literature nor in technical practice. The only evaluation parameter, that can be found is a sort of specific energy consumption (SEC) without any clear indications about the involved calculation terms, definition of hypotheses, or environmental conditions. The current work is a first proposal of an indicator to standardise the AWG efficiency evaluation. The indicator is called WET (Water Energy Transformation); it states water production as a useful effect of an AWG machine and calculates its energy performance with an approach similar to COP (Coefficient of Performance) and EER (Energy Efficiency Ratio) evaluation. The indicator is meant to be a normalised tool that permits comparing different AWG machines, but it is also the first part of a wider study, currently under development that is oriented to obtain a global index formulation that combines WET itself, EER and COP, and it is intended for a comprehensive evaluation of all the useful effects of a reverse cycle in integrated machines, in compliance with the current efficiency evaluation approach. The current paper presents the WET equation, with a discussion about involved terms, a set of normalised calculation conditions and some application examples, including a comparison with SEC.


2021 ◽  
Vol 42 (3) ◽  
pp. 349-369
Author(s):  
Robert Cohen ◽  
Karl Desai ◽  
Jennifer Elias ◽  
Richard Twinn

The UKGBC Net Zero Carbon Buildings Framework was published in April 2019 following an industry task group and extensive consultation process. The framework acts as guidance for achieving net zero carbon for operational energy and construction emissions, with a whole life carbon approach to be developed in the future. In consultation with industry, further detail and stricter requirements are being developed over time. In October 2019, proposals were set out for industry consultation on minimum energy efficiency targets for new and existing commercial office buildings seeking to achieve net zero carbon status for operational energy today, based on the performance levels that all buildings will be required to achieve by 2050. This was complemented by modelling work undertaken by the LETI network looking into net zero carbon requirements for new buildings. In January 2020 UKGBC published its guidance on the levels of energy performance that offices should target to achieve net zero and a trajectory for getting there by 2035. This paper describes the methodology behind and industry perspectives on UKGBC’s proposals which aim to predict the reduction in building energy intensity required if the UK’s economy is to be fully-powered by zero carbon energy in 2050. Practical application: Many developers and investors seeking to procure new commercial offices or undertake major refurbishments of existing offices are engaging with the ‘net zero carbon’ agenda, now intrinsic to the legislative framework for economic activity in the UK. A UKGBC initiative effectively filled a vacuum by defining a set of requirements including energy efficiency thresholds for commercial offices in the UK to be considered ‘net zero carbon’. This paper provides all stakeholders with a detailed justification for the level of these thresholds and what might be done to achieve them. A worked example details one possible solution for a new office.


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