scholarly journals Multi-Country Analysis on Energy Savings in Buildings by Means of a Micro-Solar Organic Rankine Cycle System: A Simulation Study

Environments ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 119 ◽  
Author(s):  
Alessia Arteconi ◽  
Luca Del Zotto ◽  
Roberto Tascioni ◽  
Khamid Mahkamov ◽  
Chris Underwood ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Energy Demand ◽  
Energy Use ◽  
Energy Savings ◽  
Organic Rankine Cycle ◽  
Cost Savings ◽  
Rankine Cycle ◽  
Primary Energy ◽  
Operational Cost ◽  
The North

In this paper, the smart management of buildings energy use by means of an innovative renewable micro-cogeneration system is investigated. The system consists of a concentrated linear Fresnel reflectors solar field coupled with a phase change material thermal energy storage tank and a 2 kWe/18 kWth organic Rankine cycle (ORC) system. The microsolar ORC was designed to supply both electricity and thermal energy demand to residential dwellings to reduce their primary energy use. In this analysis, the achievable energy and operational cost savings through the proposed plant with respect to traditional technologies (i.e., condensing boilers and electricity grid) were assessed by means of simulations. The influence of the climate and latitude of the installation was taken into account to assess the performance and the potential of such system across Europe and specifically in Spain, Italy, France, Germany, U.K., and Sweden. Results show that the proposed plant can satisfy about 80% of the overall energy demand of a 100 m2 dwelling in southern Europe, while the energy demand coverage drops to 34% in the worst scenario in northern Europe. The corresponding operational cost savings amount to 87% for a dwelling in the south and at 33% for one in the north.

scholarly journals Experimental investigation of domestic micro-CHP based on the gas boiler fitted with ORC module

2016 ◽  
Vol 37 (3) ◽  
pp. 79-93 ◽  
Author(s):  
Jan Wajs ◽  
Dariusz Mikielewicz ◽  
Michał Bajor ◽  
Zbigniew Kneba
Keyword(s):  
Energy Demand ◽  
Electricity Generation ◽  
Electric Energy ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Future Generation ◽  
Working Fluid ◽  
Ethanol Vapour ◽  
System User ◽  
Generation Unit

AbstractThe results of investigations conducted on the prototype of vapour driven micro-CHP unit integrated with a gas boiler are presented. The system enables cogeneration of heat and electric energy to cover the energy demand of a household. The idea of such system is to produce electricity for own demand or for selling it to the electric grid – in such situation the system user will became the prosumer. A typical commercial gas boiler, additionally equipped with an organic Rankine cycle (ORC) module based on environmentally acceptable working fluid can be regarded as future generation unit. In the paper the prototype of innovative domestic cogenerative ORC system, consisting of a conventional gas boiler and a small size axial vapour microturbines (in-house designed for ORC and the commercially available for Rankine cycle (RC)), evaporator and condenser were scrutinised. In the course of study the fluid working temperatures, rates of heat, electricity generation and efficiency of the whole system were obtained. The tested system could produce electricity in the amount of 1 kWe. Some preliminary tests were started with water as working fluid and the results for that case are also presented. The investigations showed that domestic gas boiler was able to provide the saturated/superheated ethanol vapour (in the ORC system) and steam (in the RC system) as working fluids.

scholarly journals Energy saving potential of occupancy sensors in intermittent-use space types.

2021 ◽  
Author(s):  
◽  
Georgia Alexander
Keyword(s):  
Time Delay ◽  
Energy Saving ◽  
Energy Use ◽  
Energy Savings ◽  
Cost Savings ◽  
Sensor Technology ◽  
Building Industry ◽  
User Survey ◽  
User Perceptions ◽  
Energy Saving Potential

<p>For decades, studies have been suggesting the idea of occupancy sensors in intermittent use spaces for energy savings. This work investigates the potential energy savings of occupancy sensors in hallways, stairwells, seminar rooms and lavatories of an education building. Lighting is one of the largest consumers of energy in the building industry and these space types are often fully illuminated for long periods of vacancy. Lighting is for the user, not the building. Discussions centre around light use habits, energy saving behaviours and sensor technology such as time delay and daylight sensors. The experiment uses wireless light sensors and PIR sensors to measure light energy use and occupant use of 20 intermittent use spaces. A user survey was planned to run alongside the experiment to investigate user perceptions of changes in lighting but was discontinued due to unresolved software issues. Results of the experiment encouraged the use of occupancy sensors in intermittent use spaces. Lavatories attained highest energy saving potential 54%, seminar rooms highest annual cost savings per fitting $15.47 and highest annual energy savings 482kWh and hallways calculated the quickest payback of 8.6 years. Hallways, stairwells, seminar rooms and lavatories all offer potential for energy savings, supporting the theoretical ideas and success of occupancy sensors in intermittent use spaces.</p>

scholarly journals Humidity-Sensitive Demand-Controlled Ventilation Applied to Multi-Unit Residential Building – Performance and Energy Consumption in Dfb Continental Climate

2020 ◽  
Author(s):  
Jerzy Sowa ◽  
Maciej Mijakowski
Keyword(s):  
Energy Consumption ◽  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Ventilation System ◽  
Residential Building ◽  
Primary Energy ◽  
Controlled Ventilation ◽  
Demand Controlled Ventilation ◽  
Continental Climate

A humidity-sensitive demand-controlled ventilation system is known for many years. It has been developed and commonly applied in regions with an oceanic climate. Some attempts were made to introduce this solution in Poland in a much severe continental climate. The article evaluates this system's performance and energy consumption applied in an 8-floor multi-unit residential building, virtual reference building described by the National Energy Conservation Agency NAPE, Poland. The simulations using the computer program CONTAM were performed for the whole hating season for Warsaw's climate. Besides passive stack ventilation that worked as a reference, two versions of humidity-sensitive demand-controlled ventilation were checked. The difference between them lies in applying the additional roof fans that convert the system to hybrid. The study confirmed that the application of demand-controlled ventilation in multi-unit residential buildings in a continental climate with warm summer (Dfb) leads to significant energy savings. However, the efforts to ensure acceptable indoor air quality require hybrid ventilation, which reduces the energy benefits. It is especially visible when primary energy use is analyzed.

Meanline Analysis and CFD Study of a Radial Inflow Turbine With Vaneless Distributor for Low Temperature Organic Rankine Cycle

2020 ◽  
Author(s):  
M. Deligant ◽  
S. Braccio ◽  
T. Capurso ◽  
F. Fornarelli ◽  
M. Torresi ◽  
...  
Keyword(s):  
Energy Demand ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Low Grade ◽  
Heat Sources ◽  
Turbine Wheel ◽  
Good Efficiency ◽  
Low Grade Heat

Abstract The Organic Rankine Cycle (ORC) allows the conversion of low-grade heat sources into electricity. Although this technology is not new, the increase in energy demand and the need to reduce CO2 emissions create new opportunities to harvest low grade heat sources such as waste heat. Radial turbines have a simple construction, they are robust and they are not very sensitive to geometry inaccuracies. Most of the radial inflow turbines used for ORC application feature a vaned nozzle ensuring the appropriate distribution angle at the rotor inlet. In this work, no nozzle is considered but only the vaneless gap (distributor). This configuration, without any vaned nozzle, is supposed to be more flexible under varying operating conditions with respect to fixed vanes and to maintain a good efficiency at off-design. This paper presents a performance analysis carried out by means of two approaches: a combination of meanline loss models enhanced with real gas fluid properties and 3D CFD computations, taking into account the entire turbomachine including the scroll housing, the vaneless gap, the turbine wheel and the axial discharge pipe. A detailed analysis of the flow field through the turbomachine is carried out, both under design and off design conditions, with a particular focus on the entropy field in order to evaluate the loss distribution between the scroll housing, the vaneless gap and the turbine wheel.

Near Optimal Receding Horizon Control of Thermal Energy Storage

2021 ◽  
pp. 1-13
Author(s):  
Omer Ahmed Qureshi ◽  
Peter R. Armstrong
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Savings ◽  
Search Algorithm ◽  
Cost Savings ◽  
Weather Conditions ◽  
Receding Horizon Control ◽  
Receding Horizon ◽  
Favorable Weather

Abstract Efficient plant operation can be achieved by properly loading and sequencing available chillers to charge and discharge a thermal energy storage (TES) reservoir at optimal rates and times. TES charging sequences are often determined by heuristic rules that typically aim to reduce utility costs under time of use rates. However, such rules of thumb may result in significantly sub optimal performance on somedays. Rigorous optimization, on the other hand, is computationally expensive and can be unreliable as well if not carefully implemented. Receding Horizon Control (RHC) using the novel finite search algorithm is reliable and can reach ~80% of achievable energy efficiency and/or peak shifting capacity has been our target. A novel algorithm is developed to reliably achieve near optimal control for charging the stratified sensible cool storage reservoir of a chiller plant. The algorithm provides a constant COP (or cost per ton-hour) for 24-hr dispatch plan under which chillers operate during most favorable weather conditions. Analysis of four hot climates, ranging from humid to dry, indicates 2.4~2.6% energy savings under a flat electricity rate relative to the same plant operating without TES. Annual cost savings from 6% to 9% was found for electricity billed under a simple (10am-10pm) time-of-use rate with no demand charge and no ratchet component.

scholarly journals A Hot Water Split-Flow Dual-Pressure Strategy to Improve System Performance for Organic Rankine Cycle

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3345 ◽  
Author(s):  
Shiqi Wang ◽  
Zhongyuan Yuan
Keyword(s):  
Output Power ◽  
Thermal Energy ◽  
System Performance ◽  
Industrial Waste ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Inlet Temperature ◽  
Split Flow ◽  
Net Power Output

The organic Rankine cycle (ORC) is widely used to recover industrial waste heat. For an ORC system using industrial waste hot water as a heat source, a novel hot water split-flow dual-pressure organic Rankine cycle (SFD-ORC) system is developed to improve the performance of the ORC. The maximum net power output was selected to compare three ORC systems, including basic ORC (B-ORC), conventional dual-pressure ORC (CD-ORC) and SFD-ORC. A genetic algorithm (GA) was used to optimize the parameters to search the maximum net power output of ORCs. The maximum net output power was taken as the standard of performance evaluation. The results show that, under the same hot water inlet temperature condition, the optimal hot water outlet temperature of B-ORC is much higher than that of CD-ORC and SFD-ORC, which indicates that less thermal energy could be utilized to convert to power in B-ORC. The optimal hot water temperature at the outlet of evaporator 1 in SFD-ORC is higher than that in CD-ORC, which means SFD-ORC could make more efficient use of the high-grade thermal energy of hot water. The SFD-ORC could obtain the highest net output power under the optimal parameter conditions, followed by the CD-ORC system, while the B-ORC has the lowest net output power. Moreover, with the increase in the hot water inlet temperature, the advantage of SFD-ORC becomes increasingly obvious. When the hot water inlet temperature is 90 °C, the net output power of SFD-ORC at is 6.22% higher than that of CD-ORC. The net output power of SFD-ORC at 130 °C increases to 9.7% higher than that of CD-ORC. The SFD-ORC presents better system performance and has great engineering application potential.

scholarly journals Advanced Control of a District Heating System with High Residential Domestic Hot Water Demand

2020 ◽  
Vol 160 ◽  
pp. 01004 ◽  
Author(s):  
Stanislav Chicherin ◽  
Lyazzat Junussova ◽  
Timur Junussov
Keyword(s):  
Energy Demand ◽  
Energy Use ◽  
District Heating ◽  
Heating System ◽  
Primary Energy ◽  
Hot Water ◽  
District Heating System ◽  
Domestic Hot Water ◽  
Extreme Load ◽  
Flow Controller

Proper adjustment of domestic hot water (DHW) load structure can balance energy demand with the supply. Inefficiency in primary energy use prompted Omsk DH company to be a strong proponent of a flow controller at each substation. Here the return temperature is fixed to the lowest possible value and the supply temperature is solved. Thirty-five design scenarios are defined for each load deviation index with equally distributed outdoor temperature ranging from +8 for the start of a heating season towards extreme load at temperature of -26°C. All the calculation results are listed. If a flow controller is installed, the customers might find it suitable to switch to this type of DHW supply. Considering an option with direct hot water extraction as usual and a flow controller installed, the result indicates that the annual heat consumption will be lower once network temperatures during the fall or spring months are higher. The heat load profiles obtained here may be used as input for a simulation of a DH substation, including a heat pump and a tank for thermal energy storage. This design approach offers a quantitative way of sizing temperature levels in each DH system according to the listed methodology and the designer's preference.

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