scholarly journals Application of a Lumped Multi-Section Model for Analyzing the Thermal Performance of a Small-Scale Biomass Boiler

2021 ◽  
Author(s):  
Sylwia Polesek-Karczewska ◽  
Izabela Wardach-Święcicka ◽  
Dariusz Kardaś ◽  
Tomasz Turzyński
Keyword(s):  
Thermal Performance ◽  
Flue Gas ◽  
Cell Model ◽  
Measurement Data ◽  
Thermal Characteristics ◽  
Small Scale ◽  
Outlet Temperature ◽  
Tube Heat Exchanger ◽  
Biomass Boiler ◽  
Thermal Oil

AbstractThe stationary lumped-cell model was developed and used to simulate the thermal characteristics of domestic biomass boiler with helically coiled tube heat exchanger (HCHE). The device serves as the heat source for ORC (Organic Rankine Cycle) unit and utilizes the thermal oil as the medium transferring the heat to the unit. Most of studies available in the literature refer to the CFD simulations for water flow in tube coils or in one- or two-turn coil elements. These investigations are basically focused on the determination of Nusselt number. The proposed herein model aims at determining the thermal performance of flue gas-oil HCHE while providing low CPU time. To demonstrate the model possibilities, it was used to predict the flue gas temperatures at the inlet and outlet from the heat exchange zone, based on measurement data regarding the outlet temperature of thermal oil. Six test series were considered. The computation results appeared to be in satisfactory agreement with experimental results (the discrepancies do not exceed 12%). The investigations showed that the used approach may be recommended as an alternative method that allows for fast prediction of thermal parameters for units of complex geometries, in particular the multi-coil heat exchangers.

scholarly journals Study of PTC System with Rectangular Cavity Receiver with Different Receiver Tube Shapes Using Oil, Water and Air

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2114
Author(s):  
Alireza Rafiei ◽  
Reyhaneh Loni ◽  
Gholamhassan Najafi ◽  
Talal Yusaf
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Energy Performance ◽  
Rectangular Cavity ◽  
Smooth Tube ◽  
Heat Transfer Fluid ◽  
Outlet Temperature ◽  
Solar Heat ◽  
Corrugated Tube ◽  
Thermal Oil

Today, application of cavity receivers in solar concentrator systems is suggested as an interesting and novelty research subject for increasing thermal performance. In this research, a parabolic trough concentrator (PTC) with a rectangular cavity receiver was energetically investigated. The cavity receiver was studied with smooth and corrugated tubes. Different solar heat transfer fluids were considered, including water, air, and thermal oil. The effect of different operational parameters, as well as structural parameters, was investigated. The results showed that the linear rectangular cavity receiver with corrugated tube showed higher amounts of the absorbed heat and energy performance compared to the smooth tube as the cavity tube. Thermal performance of the rectangular cavity was improved using the application of water as the solar heat transfer fluid, which was followed by thermal oil and, finally, air, as the solar heat transfer fluid. Finally, it could be recommended that the rectangular cavity receiver with smooth tube using air as the solar heat transfer fluid is more appropriate for coupling this system with a Bryton cycle, whereas the rectangular cavity receiver with the corrugated tube using water or oil as the solar heat transfer fluid is recommended for achieving higher outlet temperature of the heat transfer fluid.

scholarly journals Design of a 1 t/h Biomass Chain Boiler and ιts Fuel Adaptability Analysis

2020 ◽  
Vol 13 (5) ◽  
pp. 132-142
Author(s):  
Fu Chengguo ◽  
◽  
Feng Yipeng ◽  
Tian Yishui ◽  
Liang Mingchao ◽  
...  
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Pollutant Emissions ◽  
National Standard ◽  
Pinus Koraiensis ◽  
Air Distribution ◽  
Small Scale ◽  
Biomass Boiler ◽  
Adaptation Test ◽  
The Mean

The arch is an important component of a biomass boiler. Initial arch design of most boilers is generally gained through manual computation, thus resulting in uncertain reasonability of flue gas flow. Moreover, biomass fuels in the market have instable characteristics, which influence the utilization of biomass energies considerably. To address the problems concerning reasonable flue gas flow caused by the collaborative design of arch and air staging and the combustion adaptability of fuels, a cold modeling experiment of a 1 t/h biomass boiler under different staged air distribution ratios when the rear arch coverage varies was conducted using Fluent software in this study after thermal performance computation and initial structural design of grate and furnace. Furthermore, a boiler performance test based on main fuels and a combustion adaptation test of auxiliary fuels were also performed. The experiments show that the best flue gas flow in the furnace is achieved when the rear arch coverage is 60% and the primary–secondary air distribution ratio is 4:6. The mean boiler efficiency and the mean boiler heat output are 81.26% and 715.76 kW/h by using Pinus koraiensis pellets, wood–straw mixed pellets, and cotton straw briquettes as main fuels; and the tested pollutant emissions are in compliance with the limits of the national standard. The results of the combustion adaptation test reveal that the excessive particle size, the high ash content and the relatively low calorific value of biomass molded fuels are all against the combustion of biomass boilers. Fuel upgrading based on washing process and other methods is suggested. This study can provide references to the performance optimization of traditional small-scale biomass chain heating boilers.

scholarly journals Small-scale lab analysis of the ground freezing effect on the thermal performance of a Flat-Panel ground heat exchanger

Geothermics ◽  
2018 ◽  
Vol 74 ◽  
pp. 247-254 ◽  
Author(s):  
Jingyu Cao ◽  
Michele Bottarelli ◽  
Marco Bortoloni ◽  
Gang Pei
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Small Scale ◽  
Ground Heat Exchanger ◽  
Flat Panel ◽  
Ground Freezing

Evaluating dynamic thermal performance of building envelope components using small-scale calibrated hot box tests

2021 ◽  
pp. 111342
Author(s):  
Zhenglai Shen ◽  
Adam L. Brooks ◽  
Yawen He ◽  
Som S. Shrestha ◽  
Hongyu Zhou
Keyword(s):  
Thermal Performance ◽  
Building Envelope ◽  
Small Scale

Pilot test of environment-friendly catalysts for the DeNOx of low-temperature flue gas from a coal-fired plant

2021 ◽  
Author(s):  
Lin Guo ◽  
Jianjiang Lu ◽  
Yonggang Zhao ◽  
Chengzhi Wang ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Energy Saving ◽  
Flue Gas ◽  
Small Scale ◽  
Pilot Test ◽  
Environment Friendly ◽  
Efficient Environment

Efficient, environment-friendly, and energy-saving low-temperature denitration (DeNOx) catalysts, applicable in practical flue gas, has a widespread market for use in small-scale boilers. A novel Ce-based low-temperature honeycomb catalyst was tested...

scholarly journals Thermal Impacts of Vertical Greenery Systems

2014 ◽  
Vol 14 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Tabassom Safikhani ◽  
Aminatuzuhariah Megat Abdullah ◽  
Dilshan Remaz Ossen ◽  
Mohammad Baharvand
Keyword(s):  
Thermal Performance ◽  
Modern Architecture ◽  
Small Scale ◽  
Heat Transmission ◽  
Indoor Temperature ◽  
Experimental Procedure ◽  
Hot And Humid Climates ◽  
Living Wall ◽  
Green Façade ◽  
Green Facade

Abstract - Using vertical greenery systems to reduce heat transmission is becoming more common in modern architecture. Vertical greenery systems are divided into two main categories; green facades and living walls. This study aims to examine the thermal performance of vertical greenery systems in hot and humid climates. An experimental procedure was used to measure indoor temperature and humidity. These parameters were also measured for the gap between the vertical greenery systems and wall surfaces. Three boxes were used as small-scale rooms. Two boxes were provided with either a living wall or a green facade and one box did not have any greenery (benchmark). Blue Trumpet Vine was used in the vertical greenery systems. The data were recorded over the course of three sunny days in April 2013. An analyses of the results showed that the living wall and green facade reduced indoor temperature up to 4.0 °C and 3.0 °C, respectively. The living wall and green facade also reduced cavity temperatures by 8.0 °C and 6.5 °C, respectively.

A Novel Turbulent Aggregation Device for Flue Gas

2014 ◽  
Vol 955-959 ◽  
pp. 2425-2429 ◽  
Author(s):  
Yun Fei Li ◽  
Jian Guo Yang ◽  
Yan Yan Wang ◽  
Xiao Guo Wang
Keyword(s):  
Size Distribution ◽  
Flue Gas ◽  
Large Scale ◽  
Balance Model ◽  
Small Scale ◽  
Multiphase Model ◽  
Specific Performance ◽  
Particles Size Distribution ◽  
Scale Turbulence ◽  
Eulerian Multiphase Model

The purpose of this study is to construct a turbulent aggregation device which has specific performance for fine particle aggregation in flue gas. The device consists of two cylindrical pipes and an array of vanes. The pipes extending fully and normal to the gas stream induce large scale turbulence in the form of vortices, while the vanes downstream a certain distance from the pipes induce small one. The process of turbulent aggregation was numerically simulated by coupling the Eulerian multiphase model and population balance model together with a proposed aggregation kernel function taking the size and inertia of particles into account, and based on data of particles’ size distribution measured from the flue of one power plant. The results show that the large scale turbulence generated by pipes favours the aggregation of smaller particles (smaller than 1μm) notably, while the small scale turbulence benefits the aggregation of bigger particles (larger than 1μm) notably and enhances the uniformity of particle size distribution among different particle groups.

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