Control Strategy for the Optimal Operation of a Solar Cooling Installation

2012 ◽  
Author(s):  
Vittorio Verda ◽  
Giorgia Baccino ◽  
Stefano Pizzuti
Keyword(s):  
Energy Consumption ◽  
Solar Radiation ◽  
Control Strategy ◽  
Primary Energy ◽  
Optimal Operation ◽  
Hot Water ◽  
Objective Functions ◽  
Solar Cooling ◽  
Partial Load ◽  
Input Variables

In this paper, a solar cooling installation is analyzed with the aim of optimizing its performances. The system consists of vacuum solar collectors, which supply hot water to a LiBr absorption chiller. A boiler can be used to supply an additional amount of hot water in the case of insufficient solar radiation. In addition, a vapor compression chiller operates as a backup system and integrates the solar driven system in the case of large cooling request. Such system gives multiple operating options, especially at partial load. A model of the system is presented and applied to the real plant. It is shown that if a multi-objective optimization is performed, considering minimum primary energy consumption from fossil fuel and maximum utilization of the absorption system, a Pareto front is obtained. This occurs because the two objective functions are competing. A control strategy based on the use of neural networks is presented. Input variables are the solar radiation, ambient temperature and the cooling request. In this work the control strategy is adjusted in order to reach the minimum fossil energy consumption, but the same approach can be applied with other objective functions.

Solar Thermal Driven Cooling System for a Data Center in Albuquerque New Mexico

2010 ◽  
Author(s):  
N. Fumo ◽  
V. Bortone ◽  
J. C. Zambrano
Keyword(s):  
Energy Consumption ◽  
Data Center ◽  
Data Centers ◽  
Primary Energy ◽  
Continuous Operation ◽  
Solar Thermal ◽  
Primary Energy Consumption ◽  
Solar Collectors ◽  
Absorption Chiller ◽  
Solar Cooling

Data centers are facilities that primarily contain electronic equipment used for data processing, data storage, and communications networking. Regardless of their use and configuration, most data centers are more energy intensive than other buildings. The continuous operation of Information Technology equipment and power delivery systems generates a significant amount of heat that must be removed from the data center for the electronic equipment to operate properly. Since data centers spend up to half their energy on cooling, cooling systems becomes a key factor for energy consumption reduction strategies and alternatives in data centers. This paper presents a theoretical analysis of an absorption chiller driven by solar thermal energy as cooling plant alternative for data centers. Source primary energy consumption is used to compare the performance of different solar cooling plants with a standard cooling plant. The solar cooling plants correspond to different combinations of solar collector arrays and thermal storage tank, with a boiler as source of energy to ensure continuous operation of the absorption chiller. The standard cooling plant uses an electric chiller. Results suggest that the solar cooling plant with flat-plate solar collectors is a better option over the solar cooling plant with evacuated-tube solar collectors. However, although solar cooling plants can decrease the primary energy consumption when compared with the standard cooling plant, the net present value of the cost to install and operate the solar cooling plants are higher than the one for the standard cooling plant.

scholarly journals Optimization of a Wood Pellet Boiler System Combined with CO2HPs in a Cold Climate Area in Japan

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5531 ◽  
Author(s):  
Taro Mori ◽  
Yusuke Iwama ◽  
Hirofumi Hayama ◽  
Emad Mushtaha
Keyword(s):  
Energy Consumption ◽  
Water Supply ◽  
Co2 Emissions ◽  
Primary Energy ◽  
Cold Climate ◽  
Hot Water ◽  
Water Volume ◽  
Primary Energy Consumption ◽  
Wood Pellet ◽  
Hot Water Supply

Hot water supply is one of the leading consumers of energy in the building sector in cold climate areas. The use of woody biomass is effective in reducing CO2 emissions in hot-water supply systems. This report deals with a system that combines a wood pellet boiler (PB) and a heat pump system with CO2 (CO2HP) that is used in a facility for disabled people. The following research was conducted. The operation of a hybrid system combining a PB and CO2HPs was investigated. While operating the system, four specific operations were developed as countermeasures to save on costs and reduce system troubles while reducing CO2 emissions. The processes and results are introduced. Numerical simulations were carried out to optimize the operation. The hot water temperature, water volume, and hot water loads were simulated. The influence of the water volume ratio on the cost and primary energy consumption under the requirements for safe system operation was studied. The regional economic ripple effects (REREs) of this system were studied. The wood pellet boiler is not only a measure for reducing primary energy consumption but can also play an important role in a regional economy for sustainable development in countries that import energy resources such as Japan.

Primary energy consumption of the dwelling with solar hot water system and biomass boiler

2014 ◽  
Vol 87 ◽  
pp. 1151-1161 ◽  
Author(s):  
Mihaela Berković-Šubić ◽  
Martina Rauch ◽  
Damir Dović ◽  
Mladen Andrassy
Keyword(s):  
Energy Consumption ◽  
Water System ◽  
Primary Energy ◽  
Hot Water ◽  
Primary Energy Consumption ◽  
Biomass Boiler

scholarly journals Energy Performance Optimization in a Condensing Boiler

2021 ◽  
Vol 9 (1) ◽  
pp. 6
Author(s):  
Diego Fernández-Cheliz ◽  
Eloy Velasco-Gómez ◽  
Juan Peral-Andrés ◽  
Ana Tejero-González
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
Performance Optimization ◽  
Energy Performance ◽  
Primary Energy ◽  
Operating Conditions ◽  
Hot Water ◽  
Operating Parameters ◽  
Climate Conditions ◽  
Lower Heating Value

In Europe, primary energy consumption in buildings accounts for up to 25–40%, depending on the climate conditions. Space heating and Domestic Hot Water (DHW) contribute significantly to this energy consumption. Among the most common sources for heat generation in these appliances is natural gas. Condensing boilers can surpass the 100% energy performance over the lower heating value, if the operating conditions enable the water vapor in the exhaust gases to condensate. Consequently, optimizing the operating parameters of condensing boilers is necessary to decrease fuel consumption without hindering water heating needs. The present work presents an experimental approach to the operating parameters of a condensing boiler that works with natural gas. The aim is to develop a theoretical model that relates the energy performance to the water temperature set by the final user and the excess air set by the maintenance staff.

scholarly journals The Influence of Energy Renovation on the Change of Indoor Temperature and Energy Use

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3179 ◽  
Author(s):  
Anti Hamburg ◽  
Targo Kalamees
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Use ◽  
Primary Energy ◽  
Hot Water ◽  
Indoor Temperature ◽  
Research Issues ◽  
Apartment Buildings ◽  
Electricity Use ◽  
Heating Energy Consumption

The aim of the renovation of apartment buildings is to lower the energy consumption of those buildings, mainly the heating energy consumption. There are few analyses regarding those other energy consumptions which are also related to the primary energy need for calculating the energy efficiency class, including the primary energy need of calculated heating, domestic hot water (DHW), and household electricity. Indoor temperature is directly connected with heating energy consumption, but it is not known yet how much it will change after renovation. One of the research issues relates to the change of electricity and DHW usage after renovation and to the question of whether this change is related to the users’ behavior or to changes to technical solutions. Thirty-five renovated apartment buildings have been analyzed in this study, where the data of indoor temperature, airflow, and energy consumption for DHW with and without circulation and electricity use in apartments and common rooms has been measured. During research, it turned out that the usage of DHW without circulation and the usage of household electricity do not change after renovation. Yet there is a major increase in indoor temperature and DHW energy use in buildings that did not have circulation before the renovation. In addition, a small increase in the use of electricity in common areas was discovered. This study will offer changes in calculations for the energy efficiency number.

Comparing Energy and Cost Optimization in Distributed Energy Systems Management

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Andrea Luigi Facci ◽  
Luca Andreassi ◽  
Fabrizio Martini ◽  
Stefano Ubertini
Keyword(s):  
Time Series ◽  
Energy Consumption ◽  
Internal Combustion Engine ◽  
Objective Function ◽  
Distributed Generation ◽  
Control Strategy ◽  
Combustion Engine ◽  
Energy Systems ◽  
Primary Energy ◽  
Primary Energy Consumption

Distributed generation, despite not being a new concept, is assuming a leading role in the field of energy conversion, as it should contribute to the enhancement of efficiency, flexibility, and reliability of national energy systems. However, it also noted that the effective performances of small and flexible power plants is critically influenced by their actual control strategy. Moreover, it is not trivial to identify a univocal parameter to evaluate the plant performance. For instance, cost evaluation clearly responds to an industrial view of the energy supply problem, while energy consumption or polluting emissions comply with a socio economic approach. In this scenario, the optimization of the plant management is a valuable instrument to gain insight on their behavior as the control strategy is varied, as well as to promote the distributed generation development, by maximizing the plants performances. In this paper, we further develop a graph based optimization methodology to optimize the set-point of an internal combustion engine based plant used to satisfy a hospital energy load, under different seasonal load conditions (winter, summer, and transitional seasons) and energy prices. Specifically, in order to dissect the effects of the objective function selection, two different optimization criteria are considered, namely economical optimization and primary energy consumption minimization. In particular, we focus on the features of the prime mover (i.e., the internal combustion engine) control strategy and on its drivers, as a function of the prescribed objective function. Results demonstrate that in the actual Italian energy market, cost minimization does not match primary energy consumption minimization, because the latter is only influenced by energy demand time series, and equipments performance, while the former is fundamentally driven by the electricity prices time series.

scholarly journals Cost-Benefit Analysis of Hybrid Photovoltaic/Thermal Collectors in a Nearly Zero-Energy Building

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1582 ◽  
Author(s):  
Conti ◽  
Schito ◽  
Testi
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Electrical Energy ◽  
Energy System ◽  
Primary Energy ◽  
Hot Water ◽  
Solar Thermal ◽  
Primary Energy Consumption ◽  
Solar Thermal Energy ◽  
Zero Energy

This paper analyzes the use of hybrid photovoltaic/thermal (PVT) collectors in nearly zero-energy buildings (NZEBs). We present a design methodology based on the dynamic simulation of the whole energy system, which includes the building energy demand, a reversible heat pump as generator, the thermal storage, the power exchange with the grid, and both thermal and electrical energy production by solar collectors. An exhaustive search of the best equipment sizing and design is performed to minimize both the total costs and the non-renewable primary energy consumption over the system lifetime. The results show that photovoltaic/thermal technology reduces the non-renewable primary energy consumption below the nearly zero-energy threshold value, assumed as 15 kWh/(m2·yr), also reducing the total costs with respect to a non-solar solution (up to 8%). As expected, several possible optimal designs exist, with an opposite trend between energy savings and total costs. In all these optimal configurations, we figure out that photovoltaic/thermal technology favors the production of electrical energy with respect to the thermal one, which mainly occurs during the summer to meet the domestic hot water requirements and lower the temperature of the collectors. Finally, we show that, for a given solar area, photovoltaic/thermal technology leads to a higher reduction of the non-renewable primary energy and to a higher production of solar thermal energy with respect to a traditional separate production employing photovoltaic (PV) modules and solar thermal (ST) collectors.

Pumping Cost Minimization in an Existing District Heating Network

2013 ◽  
Author(s):  
Adriano Sciacovelli ◽  
Elisa Guelpa ◽  
Vittorio Verda
Keyword(s):  
Control Strategy ◽  
Urban Areas ◽  
Cost Minimization ◽  
Fluid Dynamic ◽  
District Heating ◽  
Primary Energy ◽  
Operating Conditions ◽  
Waste To Energy ◽  
District Heating System ◽  
Partial Load

District heating is expected to significantly contribute to the reduction of primary energy needs for heating in urban areas. This result is obtained through use of such as CHP systems, residual heat from industries or waste-to-energy plants, as well as the integration of renewable energies. The pumping system plays a crucial role and may significantly affect its performances. In this paper a large district heating system is considered. Various operating conditions corresponding with partial load operation are analyzed through a thermo-fluid dynamic model of the network. For each condition, the optimal set point of the various pumps is obtained. The set of optimal operating conditions is finally used to obtain a control strategy for the network. Results show that with respect to conventional control strategy significant reductions in primary energy consumption can be achieved.

Solar Thermal Driven Cooling System for a Data Center in Albuquerque New Mexico

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
N. Fumo ◽  
V. Bortone ◽  
J. C. Zambrano
Keyword(s):  
Energy Consumption ◽  
Data Center ◽  
Data Centers ◽  
Primary Energy ◽  
Continuous Operation ◽  
Solar Thermal ◽  
Primary Energy Consumption ◽  
Solar Collectors ◽  
Absorption Chiller ◽  
Solar Cooling

Data centers are facilities that primarily contain electronic equipment used for data processing, data storage, and communications networking. Regardless of their use and configuration, most data centers are more energy intensive than other buildings. The continuous operation of information technology equipment and power delivery systems generates a significant amount of heat that must be removed from the data center for the electronic equipment to operate properly. Since data centers spend up to half their energy on cooling, cooling systems becomes a key factor for energy consumption reduction strategies and alternatives in the data centers. This paper presents a theoretical analysis of an absorption chiller driven by solar thermal energy as cooling plant alternative for data centers. Source primary energy consumption is used to compare the performance of different solar cooling plants with a standard cooling plant. The solar cooling plants correspond to different combinations of solar collector arrays and thermal storage tank, with a boiler as source of energy to ensure continuous operation of the absorption chiller. The standard cooling plant uses an electric chiller. Results suggest that the solar cooling plant with flat-plate solar collectors is a better option over the solar cooling plant with evacuated-tube solar collectors. However, although solar cooling plants can decrease the primary energy consumption when compared with the standard cooling plant, the net present value of the cost to install and operate the solar cooling plants are higher than the one for the standard cooling plant.

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