scholarly journals Total System Performance Ratio—A Systems Based Approach for Evaluating HVAC System Efficiency

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5108
Author(s):  
Supriya Goel ◽  
Michael Rosenberg ◽  
Juan Gonzalez ◽  
Jérémy Lerond
Keyword(s):  
System Performance ◽  
Software Tool ◽  
The United States ◽  
Performance Ratio ◽  
System Evaluation ◽  
Total System ◽  
Hvac System ◽  
System Efficiency ◽  
Heating And Cooling ◽  
Code Structure

The prescriptive path is the most widely used approach for commercial code compliance in the United States. Though easy to implement, prescriptive approaches do not typically discriminate between minimally compliant, high-performing and poorly performing HVAC system configurations. Hence, to meet aggressive energy and carbon reduction goals, it is clear that energy codes will need to transition from prescriptive to performance-based approaches, a transition that is riddled with several challenges. This paper discusses a new HVAC system-based performance approach (HVAC System Performance) which provides a simpler solution to HVAV system evaluation compared to whole building performance, while keeping tradeoffs limited to specific building systems. The Total System Performance Ratio (TSPR) is a metric for evaluation of overall system efficiency instead of individual component efficiency, a solution which could also eventually facilitate the transition to a 100% performance-based code structure. TSPR is a ratio that compares the annual heating and cooling load of a building to the annual energy consumed by the building’s HVAC system. A calculation software tool has been developed for determining a building’s TSPR. Already incorporated into the 2018 Washington State Energy Code, this approach is also being evaluated by ASHRAE Standard 90.l Project Committee and has the potential to provide a comprehensive performance-based approach for HVAC system evaluation and analysis.

Proceeding Toward a License Application for U.S. Nuclear Waste Repository: Total System Performance Assessment Approach

2003 ◽  
Author(s):  
Jerry McNeish ◽  
Peter Swift ◽  
Rob Howard ◽  
David Sevougian ◽  
Donald Kalinich ◽  
...  
Keyword(s):  
Performance Assessment ◽  
System Performance ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Total System ◽  
License Application ◽  
Regulatory Commission ◽  
The U.S

The development of a deep geologic repository system in the United States has progressed to the preparation of an application for a license from the U.S. Nuclear Regulatory Commission. The project received site recommendation approval from the U.S. President in early 2002. The next phase of the project involves development of the license application (LA) utilizing the vast body of information accumulated in study of the site at Yucca Mountain, Nevada. Development of the license application involves analyses of the total system performance assessment (TSPA) of the repository, the TSPA-LA. The TSPA includes the available relevant information and model analyses from the various components of the system (e.g., unsaturated geologic zone, engineered system (waste packaging and drift design), and saturated geologic zone) (see Fig. 1 for nominal condition components), and unites that information into a single computer model used for evaluating the potential future performance or degradation of the repository system. The primary regulatory guidance for the repository system is found in 10 CFR 63, which indicates the acceptable risk to future populations from the repository system. The performance analysis must be traceable and transparent, with a defensible basis. The TSPA-LA is being developed utilizing state-of-the-art modeling software and visualization techniques, building on a decade of experience with such analyses. The documentation of the model and the analyses will be developed with transparency and traceability concepts to provide an integrated package for reviewers. The analysis relies on 1000’s of pages of supporting information, and multiple software and process model analyses. The computational environment represents the significant advances in the last 10 years in computer workstations. The overall approach will provide a thorough, transparent compliance analysis for consideration by the U.S. Nuclear Regulatory Commission in evaluating the Yucca Mountain repository.

scholarly journals Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Cooling System ◽  
Electrical Energy ◽  
Simulation Software ◽  
Heat Transfer Fluid ◽  
Hvac System ◽  
Dynamic Simulations ◽  
Heating And Cooling ◽  
The University

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

Considerations Regarding Anthropology in High School Curricula

1961 ◽  
Vol 20 (3) ◽  
pp. 134-140 ◽  
Author(s):  
Anthony Leeds
Keyword(s):  
High School ◽  
Rice Paddy ◽  
The United States ◽  
Cultural Relativism ◽  
School Level ◽  
Western World ◽  
Total System ◽  
High School Level ◽  
Or Economics ◽  
School Curricula

Few courses in anthropology have been taught as such at the high school level in the United States. Nevertheless, both in high schools and in elementary schools, and more particularly in the private schools, information which the anthropologists consider their own special interest has been used. Thus, children may be taught information about the Eskimo, apparently the favorite culture to represent the non-Western world and almost undoubtedly the only primitive one existing in the curriculum-makers' Baedeker, although an occasional bow in made to the American plains or Southwest. Now and then, studies of the major Asian countries are made whose focus is cultural rather than properly geographical. Other cultures, ranging up to the most complex, ordinarily appear to be brought into a curriculum more as functions of the description of the locations inhabited by humans than as descriptions, informed by some conception as to the nature of culture, of the specific cultures themselves. In short, one may safely assert, I believe, that the students get some sense of the variations exhibited by societies but mostly as curiosa and oddities of peculiar peoples. They do not get a sense of the cultural necessities of variation and differences as these derive from the technological articulations with environment. Rather, variation and differences are presented as if they were more or less accidentally associated with particular kinds of geographic features. Children appear rarely to be taught that there is such a class of events as technologies which can systematically be studied like geography or economics. Rather, they become familiar only with technical activities which they see as scattered hither and yon rather planlessly on the earth's far-away surfaces, activities such as camel-herding here, rice-paddy planting there. Certainly they get no sense of the effects of technology as a formal determinant of social structure and as conditioners of ideologies; far less are they presented, or do they achieve, a notion of culture as a total system. Much less are they led to see culture as a system which operates by its own laws, which has its own distinguishing characteristics and process, and whose variants cannot be reduced to any known ultimate value hierarchy. Thus, by learning mere esoterica, they are prevented from learning the fundamental first step required of all anthropologists, the scientific and ethical principle of cultural relativism. Consequently, too, they are prevented from learning the kind of perspective on world, culture, and self which anthropology can afford.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

scholarly journals PLANHEAT’s Satellite-Derived Heating and Cooling Degrees Dataset for Energy Demand Mapping and Planning

2019 ◽  
Vol 11 (17) ◽  
pp. 2048
Author(s):  
Sismanidis ◽  
Keramitsoglou ◽  
Barberis ◽  
Dorotić ◽  
Bechtel ◽  
...  
Keyword(s):  
Energy Demand ◽  
Near Infrared ◽  
Accuracy Assessment ◽  
Surface Air Temperature ◽  
Software Tool ◽  
Base Temperature ◽  
Low Carbon ◽  
Heating And Cooling ◽  
Air Temperatures ◽  
Infrared Imager

The urban heat island (UHI) effect influences the heating and cooling (H&C) energy demand of buildings and should be taken into account in H&C energy demand simulations. To provide information about this effect, the PLANHEAT integrated tool—which is a GIS-based, open-source software tool for selecting, simulating and comparing alternative low-carbon and economically sustainable H&C scenarios—includes a dataset of 1 × 1 km hourly heating and cooling degrees (HD and CD, respectively). HD and CD are energy demand proxies that are defined as the deviation of the outdoor surface air temperature from a base temperature, above or below which a building is assumed to need heating or cooling, respectively. PLANHEAT’s HD and CD are calculated from a dataset of gridded surface air temperatures that have been derived using satellite thermal data from Meteosat-10 Spinning Enhanced Visible and Near-Infrared Imager (SEVIRI). This article describes the method for producing this dataset and presents the results for Antwerp (Belgium), which is one of the three validation cities of PLANHEAT. The results demonstrate the spatial and temporal information of PLANHEAT’s HD and CD dataset, while the accuracy assessment reveals that they agree well with reference values retrieved from in situ surface air temperatures. This dataset is an example of application-oriented research that provides location-specific results with practical utility.

scholarly journals Performance Evaluation of 100kWp Roof-top Grid-connected PV System installed in Northern India

2019 ◽  
Vol 8 (3) ◽  
pp. 8441-8444 ◽  
Keyword(s):  
Degradation Rate ◽  
Capacity Utilization ◽  
Plant Performance ◽  
Performance Ratio ◽  
Energy Output ◽  
System Efficiency ◽  
Pv System ◽  
Utilization Factor ◽  
Northern India ◽  
Efficiency Performance

The performance of 100 kWp roof-top grid-connected PV system was evaluated. The plant was installed at PGDM building in Sharda University, Greater Noida in northern India. The plant was monitored from March 2018 to February 2019. Performance parameters such as system efficiency, performance ratio, capacity utilization factor, and degradation rate were obtained. The plant performance result was compared with the estimated results obtained from SAM and PVsyst software. The total annual energy output was found to be 16426 kWh. The annual average system efficiency and capacity utilization factor of the plant was found to be 15.62 % and 14.72 % respectively. The annual performance ratio and annual degradation rate were found to be 76% and 1.28%/year respectively. The annual performance ratio obtained from SAM and PVsyst was found to be 78% and 82% respectively. It was noticed that the measured performance ratio was highly relative with the one obtained from SAM software.

Sign in / Sign up

Export Citation Format

Share Document