Lesson 1Fundamentals of heat transfer for HVAC loads: sensible vs latent, conduction, convection, radiation, and solar gainsReviews heat transfer basics for HVAC loads, differentiating sensible and latent heat, and describing conduction, convection, radiation, and solar gains for building envelopes and internal sources in Eritrea.
Sensible versus latent heat definitionsConduction through building assembliesConvection at interior and exterior surfacesLongwave and shortwave radiation effectsSolar gains and their interaction with loadsLesson 2Solar heat gain calculations: orientation, shading factors, glass properties, and use of solar heat gain coefficientsCovers solar gains through glazing, how orientation and shading alter radiation, and applying glass properties and SHGC to estimate hourly solar cooling loads in Eritrean designs.
Solar geometry and surface orientationShading devices and shading coefficientsGlass types, coatings, and visible transmittanceUsing SHGC and area to find solar gainsTime-of-day and seasonal solar variationsLesson 3Presenting load calculation worksheets: unit conversions, consistent units (IP), and step-by-step example structureDescribes organizing and presenting load worksheets, keeping consistent IP units, key conversions, and structuring examples for traceable assumptions and results in Eritrean engineering.
Standard worksheet layout and sectionsConsistent IP units and common pitfallsKey unit conversions for load workDocumenting assumptions and inputsStep-by-step example presentationLesson 4Equipment and plug load calculations: inventorying, duty cycles, diversity factors, and internal heat distributionExplains estimating equipment and plug loads from power, duty cycles, diversity, and splitting internal heat into sensible and latent components across zones in Eritrean buildings.
Identifying equipment and plug inventoriesConnected load, demand, and duty cycleDiversity factors for receptacle loadsSensible versus latent equipment gainsZonal distribution of internal equipment heatLesson 5Ventilation and latent loads: outdoor air sensible and latent contributions, using humidity ratios and psychrometric principlesFocuses on outdoor air ventilation loads, using humidity ratios and psychrometrics to separate sensible and latent parts, and how code airflow affects cooling and dehumidification in Eritrea.
Ventilation airflow from codes and standardsOutdoor and indoor design conditionsHumidity ratio, enthalpy, and psych chartsSensible versus latent ventilation loadsPreconditioning and energy recovery impactsLesson 6Infiltration and unbalanced ventilation: estimating infiltration rates, impact on latent and sensible loadsExplains how air leakage and unbalanced ventilation impact sensible and latent loads, methods to estimate infiltration, and effects of stack, wind, and mechanical forces in Eritrean calculations.
Drivers of infiltration: wind and stackACH, CFM, and envelope leakage metricsEstimating infiltration for load designSensible and latent load from infiltrationUnbalanced ventilation and pressure effectsLesson 7Latent load estimation and psychrometrics: dew point, specific humidity, calculation of latent heat loads from people, ventilation, and processesDevelops latent load estimation with psychrometrics, covering dew point, specific humidity, and computing latent heat from people, ventilation, and processes in Eritrean buildings.
Dew point, humidity ratio, and RHPsychrometric chart navigation basicsLatent gains from occupantsLatent loads from ventilation airProcess moisture sources and dehumidificationLesson 8Load calculation approaches: manual cooling load calculations, heat balance overview, and simplified methodsIntroduces main cooling and heating load methods, including manual, heat balance, and simplified approaches, noting accuracy, inputs, and uses in Eritrean HVAC design.
Design objectives and required accuracyManual component-by-component methodsHeat balance and radiant-time-series ideasSimplified and rule-of-thumb approachesComparing methods and selecting an approachLesson 9People load calculations: sensible and latent contributions per occupant and per area, using ASHRAE tablesDetails quantifying sensible and latent heat from people using ASHRAE tables, considering activity, clothing, schedules, and converting to area-based values for Eritrea.
Metabolic rates and activity categoriesASHRAE tables for sensible and latent gainsOccupancy density and diversity factorsSchedules and peak occupancy selectionConverting per-person to per-area loadsLesson 10Combining loads and safety factors: coincident load summation, diversity, temperature delta selections, and peak load extrapolation from one floor to whole buildingShows combining component loads into system loads, applying diversity and safety factors, selecting temperature deltas, and scaling floor results to building peaks in Eritrean contexts.
Coincident versus noncoincident load summationApplying diversity to internal gainsChoosing indoor and outdoor design deltasSafety factors and avoiding oversizingScaling floor loads to whole buildingsLesson 11Envelope heat gains: conduction through walls, roof, windows using UA method and solar heat gain through glazingCovers envelope heat gains via walls, roofs, windows using UA method, temperature differences, solar surfaces, and combining conduction and solar in glazing for Eritrea.
U-values, R-values, and UA calculationsWall and roof conduction with design deltasWindow conduction and frame effectsSolar gains through glazing systemsThermal mass and time lag considerationsLesson 12Lighting load calculations: converting lighting power density to sensible heat, diversity, and control impactsExplains converting lighting power density to sensible heat gains, applying diversity and controls, accounting for schedules, dimming, and losses in Eritrean office designs.
Lighting power density and fixture dataConverting watts to sensible heat gainsLighting schedules and diversity factorsControls: occupancy and daylight dimmingBallast, driver, and luminaire losses
