scholarly journals Analysis of the temperature, humidity, and total efficiency of the air handling unit with a periodic counterflow heat exchanger

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1175-1185 ◽  
Author(s):  
Marek Jaszczur ◽  
Marek Borowski ◽  
Daniel Satola ◽  
Slawosz Kleszcz ◽  
Michal Karch
Keyword(s):  
Heat Exchanger ◽  
Energy Recovery ◽  
Energy Use ◽  
High Efficiency ◽  
Winter Period ◽  
Total Efficiency ◽  
Outdoor Air ◽  
Air Handling Unit ◽  
Energy Consuming ◽  
Real Value

In this work, thermal, humidity and enthalpy recover efficiency of innovative energy recovery exchanger is presented. The system under analysis allows adjustment of the humidity recovery especially useful in the winter period and forefend energy use for an anti-froze system of energy exchanger. It is shown that the presented method can achieve the real value for humidity and thermal efficiency above 80% and 90%, respectively. Such high efficiency was possible to obtain because the proposed system does not require energy consuming anti-freeze systems. The presented system is able to work even in extremely adverse outdoor air conditions (-20?C and humidity 100%).

scholarly journals An analysis of the innovative exhaust air energy recovery heat exchanger

2018 ◽  
Vol 240 ◽  
pp. 02003 ◽  
Author(s):  
Marek Borowski ◽  
Marek Jaszczur ◽  
Daniel Satoła ◽  
Sławosz Kleszcz ◽  
Michał Karch
Keyword(s):  
Heat Exchanger ◽  
Energy Recovery ◽  
Energy Use ◽  
Dynamic Change ◽  
Ventilation System ◽  
Primary Source ◽  
Winter Period ◽  
Recovery Efficiency ◽  
Total Energy Consumption ◽  
Result Show

Heating, ventilation and air conditioning systems are responsible for a nearly 50% of total energy consumption in operated buildings. One of the most important parts of the ventilation system is an air handling unit with a heat exchanger for energy recovery which is responsible for effective and efficient energy recovery from exhaust air. Typically heat exchangers are characterised by the producers by heat and humidity recovery efficiency up to 90% and 75% respectively. But these very high values are usually evaluated under laboratory conditions without taking into account a dynamic change of outdoor and indoor air conditions significantly affecting the recovery efficiency. In this paper, results of thermal, humidity and enthalpy recover efficiency of innovative energy recovery exchanger have been presented. The analysed system allows adjustment of the humidity recovery especially useful in the winter period and forefends energy use for an anti-froze system of energy exchanger. Presented result show that analysed innovative system can achieve the value of thermal efficiency recovery higher than 90% and efficiency of humidity recovery about 80%. This is possible because the analysed system is able to work without the use of any primary source energy or other anti-freeze systems. Presented in this research unique solution is able to work without external anti-freeze systems even in extremely adverse outdoor air conditions such as minus 20°C and humidity 100% RH.

scholarly journals Simulation of energy impact of an energy recovery ventilator in Northern housing

2021 ◽  
Vol 246 ◽  
pp. 10005
Author(s):  
Jing Li ◽  
Radu Zmeureanu ◽  
Hua Ge
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Energy Recovery ◽  
Energy Use ◽  
Energy Savings ◽  
Airflow Rate ◽  
Outdoor Air ◽  
Energy Impact ◽  
Core Energy ◽  
Air Intake

The single core Energy Recovery Ventilator (ERV) used in this study is equipped with defrost control that recirculates the exhaust indoor air, while keeps the outdoor air intake damper closed. This defrost strategy has the disadvantage of reducing the outdoor air supplied to the house, which may affect the indoor air quality. First, this paper presents new correlation-based models of supply air temperature T2 after the energy recovery core during normal and defrost operation modes based on laboratory experimental data. A pre-heating coil heats the supply air from T2 to indoor air temperature. Second, a house in Montreal (4356 HDD) is simulated as a reference using TRNSYS program. Since the program cannot simulate the operation under defrost mode, the new models are connected in TRNSYS using equation boxes. The energy use of houses at three locations in northern Canada with HDD of 8798 (Inuvik), 8888 (Kuujjuaq) and 12208 (Resolute), are also simulated, without and with ERV unit. The seasonal energy used for heating the house and pre-heating the supply air is compared with results from Montreal. Compared to the case without heat recovery, the ERV unit leads to energy savings: 24% (Montreal), 26% (Inuvik), 27% (Kuujjuaq), and 27% (Resolute). Compared to the minimum standard requirements, the outdoor airflow rate due to defrost is reduced by 4.7% (223 hours) in Montreal, 19% (1043 hours) in Inuvik, 13% (701 hours) in Kuujjuaq, and 24% (1379 hours) in Resolute.

scholarly journals Simulation of high-efficiency gyrotron with the system of multistage energy recovery

2019 ◽  
Vol 30 ◽  
pp. 02001 ◽  
Author(s):  
Pavel Trofimov ◽  
Oleg Louksha
Keyword(s):  
Electron Beam ◽  
Energy Recovery ◽  
High Efficiency ◽  
Beam Quality ◽  
Particle Interaction ◽  
Velocity Spread ◽  
Total Efficiency ◽  
Frequency Wave ◽  
Electron Efficiency ◽  
Collector Region

The results of simulations of helical electron beam formation and collecting, as well as high frequency wave-particle interaction processes, in the moderate-power experimental gyrotron with the frequency of 74.2 GHz are presented. Various methods of beam quality and electron efficiency improvement via optimization of electric and magnetic field distributions in the cathode region were realized. In the optimal operating regime with high pitch ratio and low velocity spread, the electron efficiency of about 46 % was calculated for the gyrotron with the magnetron injection gun including a control electrode and a cathode with sectioned emission. In the gyrotron collector region, a system of 4-stage electron energy recovery was used for enhancement of total efficiency of the device. By improving the quality of the electron beam and efficient energy recovery in the collector region, the total efficiency of the gyrotron equal to 71.8% was achieved.

Vapor-selective active membrane energy exchanger for high efficiency outdoor air treatment

2021 ◽  
Vol 295 ◽  
pp. 116950
Author(s):  
Andrew J. Fix ◽  
James E. Braun ◽  
David M. Warsinger
Keyword(s):  
High Efficiency ◽  
Outdoor Air ◽  
Air Treatment ◽  
Active Membrane ◽  
Membrane Energy

Optimizing Control of Dedicated Outdoor Air Systems with Energy Recovery in Commercial Buildings

2017 ◽  
Vol 143 (1) ◽  
pp. 05016004
Author(s):  
Nick Fernandez ◽  
Srinivas Katipamula ◽  
Ronald M. Underhill
Keyword(s):  
Energy Recovery ◽  
Commercial Buildings ◽  
Outdoor Air ◽  
Optimizing Control

Externally-Fired Combined Cycle Repowering of Existing Steam Plants

1993 ◽  
Author(s):  
Christian L. Vandervort ◽  
Mohammed R. Bary ◽  
Larry E. Stoddard ◽  
Steven T. Higgins
Keyword(s):  
Heat Exchanger ◽  
Steam Turbine ◽  
Gas Turbine ◽  
High Efficiency ◽  
Low Cost ◽  
Operating Experience ◽  
Capital Cost ◽  
Combined Cycle ◽  
Plant Design ◽  
Generating Capacity

The Externally-Fired Combined Cycle (EFCC) is an attractive emerging technology for powering high efficiency combined gas and steam turbine cycles with coal or other ash bearing fuels. The key near-term market for the EFCC is likely to be repowering of existing coal fueled power generation units. Repowering with an EFCC system offers utilities the ability to improve efficiency of existing plants by 25 to 60 percent, while doubling generating capacity. Repowering can be accomplished at a capital cost half that of a new facility of similar capacity. Furthermore, the EFCC concept does not require complex chemical processes, and is therefore very compatible with existing utility operating experience. In the EFCC, the heat input to the gas turbine is supplied indirectly through a ceramic heat exchanger. The heat exchanger, coupled with an atmospheric coal combustor and auxiliary components, replaces the conventional gas turbine combustor. Addition of a steam bottoming plant and exhaust cleanup system completes the combined cycle. A conceptual design has been developed for EFCC repowering of an existing reference plant which operates with a 48 MW steam turbine at a net plant efficiency of 25 percent. The repowered plant design uses a General Electric LM6000 gas turbine package in the EFCC power island. Topping the existing steam plant with the coal fueled EFCC improves efficiency to nearly 40 percent. The capital cost of this upgrade is 1,090/kW. When combined with the high efficiency, the low cost of coal, and low operation and maintenance costs, the resulting cost of electricity is competitive for base load generation.

scholarly journals Feature Identification for Non-Intrusively Extracting Occupant Energy-Use Information in Office Buildings

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Hamed Nabizadeh Rafsanjani
Keyword(s):  
Capital Investment ◽  
Energy Use ◽  
Low Cost ◽  
Specific Energy Consumption ◽  
Cost Effective ◽  
Office Buildings ◽  
Specific Power ◽  
Feature Identification ◽  
Load Monitoring ◽  
Energy Consuming

Detailed energy-use information of office buildings’ occupants is necessary to implement proper simulation/intervention techniques. However, acquiring accurate occupant-specific energy consumption in office buildings at low cost is currently a challenging task since existing intrusive load monitoring (ILM) technologies require a large capital investment to provide high-resolution electricity usage data for individual occupants. On the other hand, non-intrusive load monitoring (NILM) approaches have been proven as more cost effective and flexible approaches to provide energy-use information of individual appliances. Therefore, extending the concept of NILM to individual occupants would be beneficial. This paper proposes two occupancy-related energy-consuming features, delay interval and magnitude of power changes and evaluates their significances for extracting occupant-specific power changes in a non-intrusive manner. The proposed features were examined through implementing a logistic regression model as a predictor on aggregate energy load data collected from an office building. Hypotheses tests also confirmed that both features are statistically significant to non-intrusively derive individual occupants’ energy-use information. As the main contribution of this study, these features could be utilized in developing sophisticated NILM-based approaches to monitor individual occupant energy-consuming behavior.  

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