PDF Publication Title:
Text from PDF Page: 007
Energies 2022, 15, x FOR PEER REVIEW 7 of 22 Energies 2022, 15, 1316 7 of 22 The given dimensions refer to a multiple of the outer tube diameter. The difference The given dimensions refer to a multiple of the outer tube diameter. The difference in in performance between the two configurations was investigated in the MICRO test rig. performance between the two configurations was investigated in the MICRO test rig. All All other test rigs used the sandTES tube spacing (b in Figure 7). other test rigs used the sandTES tube spacing (b in Figure 7). The TRINI test rig was also used to investigate the influence of baffles between the The TRINI test rig was also used to investigate the influence of baffles between the tutubbeess, ,diirrecttiing the sand iinaazzigig-z-zaaggfafsahsihoinonacarcorsosstshtehteubtuebs,eass, pasicptuicrteudreindFiinguFriegu8r. eTh8e. Tuhseeuosfe boaf fbflaefsfleis ivsevreyrycocmommononininsshheell-la-anndd-t-utubbeeheeatt exchangers and waspprreevvioiouusslyly ininvveesstitgigaateteddbbyy, f,oforrexeaxmampplel,eK, Konongg[1[51]5]ananddPPeceocroara[1[61]6,]w, witihthddiffifefrernetnotuotuctocmomese.s. Figure 8. TRINI flow configurations: (a) With and (b) Without baffles. Both heating tubes (red, Figure 8. TRINI flow configurations: (a) With and (b) Without baffles. Both heating tubes (red, numbered 1 and 2) are active at the same time. numbered 1 and 2) are active at the same time. For this purpose, TRINI was also the only test rig employing two heated tubes, with For this purpose, TRINI was also the only test rig employing two heated tubes, with one on each side of the baffle in the center. one on each side of the baffle in the center. 2.2. Measurement and Evaluation 2.2. Measurement and Evaluation Two types of HTCs were measured, which are called gross and net HTC. The gross Two types of HTCs were measured, which are called gross and net HTC. The gross HTC is directly derived from the definition of the HTC to the surrounding fluidized bed: HTC is directly derived from the definition of the HTC to the surrounding fluidized bed: πΌτ±τ°τ° τ°τ° = Pel πτ°τ°‘ (1) π΄ τ° τ±π τ°τ±τ±τ° τ°τ±τ°τ° β πτ° τ± (1) τ±τ°τ° Ξ±gross = is the electric power of the heating cartridge inside one of the heat exchanger Atube Tsur f β Tbed tubes that heats the sand; π΄ is the outside surface of the heated tube; and (π β where πτ°τ°‘ where Pel is the electric power oτ°τ±fτ±tτ°he heating cartridge inside one of the heat exchanger tτ°uτ±τ°bτ°es π ) is the temperature difference between the outer tube surface and the surrounding τ±τ°τ° that heats the sand; Atube is the outside surface of the heated tube; and Tsur f β Tbed is the fluidized bed. temperature difference between the outer tube surface and the surrounding fluidized bed. The net HTC takes the heat losses caused by the fluidization gas into account: The net HTC takes the heat losses caused by the fluidization gas into account: πβπτ±(h(π )βh(π)) τ°τ°‘ .τ± τ± τ±τ° τ±τ° τ± τ±τ°€τ° πΌτ°τ°τ° = Pel β mA (hA(TAout) β hA(TAin)) (2) Ξ±= π΄τ±πτ°βπτ±τ° (2) net τ°τ±τ±τ° τ°τ±τ°τ° τ±τ°τ° τ°τ° Atube Tsur f β Tbed where πτ±τ± is the fluidization air mass flow and (hτ±(πτ±τ° τ±τ°) β hτ±(πτ±τ°€τ°)) is the difference in . specific enthalpy of air between the outlet and inlet temperatures. Heat losses caused by where mA is the fluidization air mass flow and (hA(TAout) β hA(TAin)) is the difference in the sand mass flow were ignored since the heat capacity flow of the sand far exceeded the specific enthalpy of air between the outlet and inlet temperatures. Heat losses caused by electrical heating power, making the temperature differences of the sand across the the sand mass flow were ignored since the heat capacity flow of the sand far exceeded the control volume boundaries too small to measure. electrical heating power, making the temperature differences of the sand across the control Both gross and net HTC have their uses and different justifications. While the gross volume boundaries too small to measure. HTC is better suited to describe the cooling of the heated tube, the net HTC can be used Both gross and net HTC have their uses and different justifications. While the gross to quantify the amount of heat transferred to the sand alone, which is crucial for energy HTC is better suited to describe the cooling of the heated tube, the net HTC can be used storage applications. If the exhaust air is recuperated with the supplied air, as would be to quantify the amount of heat transferred to the sand alone, which is crucial for energy the case in an energy storage application, the heat losses are largely eliminated, and the storage applications. If the exhaust air is recuperated with the supplied air, as would be the net HTC is expected to be closer to the gross HTC. case in an energy storage application, the heat losses are largely eliminated, and the net HTC iTsheexpenectitreedetloecbtericlpoosewretro(theagt)rowsassHaTssCu.med to be transferred into the fluidized bed (sanTdhaenedntfilrueideliezcatriiocnpaoiwr)e,rs(oheaallt)hweatslaossuemswederteobigentorraends.feTrrheidsisntjoustthifeieflduibdyiztehderbmedal (sand and fluidization air), so all heat losses were ignored. This is justified by thermalPDF Image | Heat Transfer between Finned Tubes
PDF Search Title:
Heat Transfer between Finned TubesOriginal File Name Searched:
energies-15-01316.pdfDIY PDF Search: Google It | Yahoo | Bing
Turbine and System Plans CAD CAM: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. More Info
Waste Heat Power Technology: Organic Rankine Cycle uses waste heat to make electricity, shaft horsepower and cooling. More Info
All Turbine and System Products: Infinity Turbine ORD systems, turbine generator sets, build plans and more to use your waste heat from 30C to 100C. More Info
CO2 Phase Change Demonstrator: CO2 goes supercritical at 30 C. This is a experimental platform which you can use to demonstrate phase change with low heat. Includes integration area for small CO2 turbine, static generator, and more. This can also be used for a GTL Gas to Liquids experimental platform. More Info
Introducing the Infinity Turbine Products Infinity Turbine develops and builds systems for making power from waste heat. It also is working on innovative strategies for storing, making, and deploying energy. More Info
Need Strategy? Use our Consulting and analyst services Infinity Turbine LLC is pleased to announce its consulting and analyst services. We have worked in the renewable energy industry as a researcher, developing sales and markets, along with may inventions and innovations. More Info
Made in USA with Global Energy Millennial Web Engine These pages were made with the Global Energy Web PDF Engine using Filemaker (Claris) software.
Sand Battery Sand and Paraffin for TES Thermo Energy Storage More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)