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Lecture Objectives:. Finish with discretization for conduction equitation Learn about linearization of radiation equation Learn about eOUEST. Top view. Homework assignment 2. T _north_o. T north_i. 2.5 m. T air_in. Surface radiation. T inter_surf. 8 m. I DIR. 8 m. conduction.
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Lecture Objectives: • Finish with discretization for conduction equitation • Learn about linearization of radiation equation • Learn about eOUEST
Top view Homework assignment 2 T_north_o Tnorth_i 2.5 m Tair_in Surface radiation Tinter_surf 8 m IDIR 8 m conduction Idif East North Teast_i Teast_o Tair_out Glass Surface radiation Idif IDIR
Tj Ti Linearization of radiation equationsSurface to surface radiation Equations for internal surfaces radiation Last term in equation can be rearranged: For unsteady steady problem: Linearized equations: Calculate h based on temperatures from previous time step Where “radiation coefficient” is:
Weather data Design condition vs. Operation condition Design whether parameters Winter • Temperature Summer • Temperature and RH - Solar radiation – clear sky no pollution
Weather data for ES analyses • Representative (typical) data • Characteristic for the location and longer period of time • TMY , TMY2, TMY3 database • Typical Meteorological Year 2 (TMY2) • data files are created from the National Solar Radiation Data Base (NSRDB) • a solar radiation and meteorological database (1961-1990 for TMY2 and 1991-2005 for TMY3)
Typical Meteorological Year • http://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/tmy3/ • Large number of locations • Very compact data base • http://www.nrel.gov/docs/fy08osti/43156.pdf • You need to use data reader converter • write your one ore use already developed
Typical Meteorological Year • Structure (many weather parameters) • Real data (no averaging) 1960 1961 1962 ………………….. 1990 January February December August
Case when HVAC controls T air Initial condition and “Warming-up” Solution Internal air Day 3 Day 1 Day 2
eQUESTsoftware http://www.doe2.com/equest/