Lesson 1Inverter (variable-speed) vs fixed-speed compressors: efficiency, part-load performance, inrush current, ambient considerationsCompare inverter and fixed-speed compressors for office applications in Botswana, focusing on efficiency ratings, part-load comfort, inrush current, electrical sizing, and performance at high and low ambient temperatures in the chosen climate like Gaborone's hot summers.
How inverter drives modulate capacityFixed-speed behaviour at part loadInrush current and electrical sizingEfficiency ratings at full and part loadAmbient temperature effects on capacityLesson 2Choosing system type: single-split vs multi-split, benefits and tradeoffsExplore how to choose between single-split and multi-split systems for a 2,000 sq ft office in Botswana, weighing zoning flexibility, installation cost, maintenance complexity, redundancy, and future expansion needs in a realistic commercial scenario.
Zoning needs and temperature control goalsPiping layout and installation constraintsCost comparison: equipment and labourService access and maintenance complexityRedundancy and impact of unit failureLesson 3Estimating internal gains from computers and office equipment (W per workstation) and occupancy schedulesQuantify internal gains from computers, monitors, printers, and people in a 2,000 sq ft office by estimating watts per workstation, diversity factors, and occupancy schedules typical in Botswana offices, then convert these gains into sensible and latent loads.
Typical W per workstation and equipmentDiversity factors for office equipment useOccupancy density and schedule profilesSeparating sensible and latent componentsConverting internal gains to BTU/h loadsLesson 4Preparing a short justification statement referencing a chosen city climate (sensible/latent balance) and recommended unit specification sheet items (capacity, SEER/IEER, sound, dimensions)Practice writing a concise justification for the selected system using a specific city climate like Gaborone, referencing sensible and latent balance, and key specification sheet items such as capacity, SEER or IEER, sound levels, and unit dimensions for local standards.
Choosing a representative city climateSummarising sensible and latent loadsReferencing capacity and efficiency ratingsIncluding sound, size, and clearance dataStructuring a clear justification paragraphLesson 5Calculating sensible and latent heat loads: people, equipment, lighting, envelopeDevelop skills to calculate sensible and latent loads from people, equipment, lighting, and the building envelope in Botswana's climate, then combine them into a total design load that reflects realistic operating conditions for the 2,000 sq ft office.
People loads: sensible and latent splitsEquipment and lighting heat gain methodsEnvelope loads: walls, roof, and glassUsing CLF or similar factors for timingCombining components into design loadLesson 6Selecting capacity in BTU/h and tons: rounding, safety factors, diversity and part-load considerationsLearn how to select system capacity in BTU/h and tons for the office in Botswana, including rounding rules, safety factors, diversity between zones, and part-load performance so that equipment runs efficiently without chronic short cycling in hot conditions.
Converting calculated load to nominal tonsRounding up or down from load resultsApplying reasonable safety factorsAccounting for diversity across office zonesChecking part-load operation and cyclingLesson 7Refrigerant options and implications for performance and serviceability (R410A, R32, others)Review common refrigerants such as R410A and R32, comparing efficiency, pressure levels, glide, flammability, and environmental impact in Botswana's context, and learn how refrigerant choice affects piping design, service tools, and future regulatory compliance.
Key properties of R410A and R32Efficiency and capacity differences by refrigerantSafety, flammability, and code requirementsImpact on piping, charge, and componentsService tools, training, and phaseout risksLesson 8Using simplified load sizing rules (BTU/ft²) and comparison with manual J style estimatesLearn how to apply simplified BTU per square foot rules for quick office load estimates in Botswana, then compare and calibrate them against Manual J style methods to understand limits, correction factors, and when detailed calculations are required.
Typical BTU/ft² ranges for office spacesAdjusting rules for climate and building qualityComparing quick rules to Manual J style resultsRecognising when rules of thumb failApplying safety factors without oversizingLesson 9Selecting auxiliary features: filtration level, noise ratings (dB), controls and connectivity optionsLearn how to select filtration levels, noise ratings, and control options that suit office comfort, indoor air quality, and IT requirements in Botswana, including filter MERV choices, dB targets, smart controls, and integration with building networks.
Choosing MERV rating and filter typeNoise criteria and target indoor dB levelsFan speed settings and sound tradeoffsThermostat types and scheduling optionsConnectivity, BACnet, and app integrationLesson 10Matching indoor unit airflow and coil selection to room sensible load and thermostat placementUnderstand how to match indoor unit airflow and coil capacity to room sensible loads in Botswana offices, while considering thermostat placement, air throw, diffuser selection, and avoiding drafts or stratification that can cause comfort complaints in office zones.
Calculating required CFM from sensible loadSelecting coils for sensible heat ratioAir throw, diffuser type, and coverageThermostat location and sensor placementAvoiding drafts, short cycling, and stratification
