Course project presentation Thursday in class Timing: 4 minutes (strictly controlled) Approximately 1 PowerPoint Slides per minute Content Problem Introduction Methodology Results Comments and recommendation You need to me your presentation before the class! 2 minutes for Question and Answers

Final project report Introduction Methodology Results Comments DO NOT submit pictures without comments Analyze the result - create diagrams and tables

Objectives Finish control systems – sequence of operation Psychrometric chart Learn about desiccant systems Psychrometric chart Learn about software for load calculation Review

HVAC Control Example 2: Dew point control (Relative Humidity control) filter fan cooling coil heating coil filter mixing damper fresh air T & RH sensors We either measure Dew Point directly or T & RH sensors substitute dew point sensor Humidity generation Heat gains We should supply air with lower humidity ratio (w) and lower temperature

Relative humidity control by cooling coil »T DP Mixture Cooling Coil Room Supply »Heating coil

Relative humidity control by cooling coil (CC) Cooling coil is controlled by T DP set-point if T DP measured > T DP set-point → send the signal to open more the CC valve if T DP measured < T DP set-point → send the signal to close more the CC valve cooling coil heating coil »mixing Fresh air T air & T DP sensors Control valves Heating coil is controlled by T air set-point if T air T air set-point → send the signal to close more the heating coil valve

Sequence of operation (ECJ research facility) »Control logic: »Mixture in zone 1: IF (( TM<TSP) & (DPTM<DPTSP) ) heating and humidifying »Heater control: IF (TSP>TSA) increase heating or IF (TSP<TSA) decrease heating »Humidifier: IF (DPTSP>DPTSA) increase humidifying or IF (DPTSP<DPTSA) decrease humid. »Mixture in zone 2: IF ((TM>TSP) & (DPTM<DPTSP) ) cooling and humidifying »Cool. coil cont.: IF (TSP TSA) decrease cooling »Humidifier: IF (DPTSP>DPTSA) increase humidifying or IF (DPTSP<DPTSA) decrease hum. »Mixture in zone 3: IF ((DPTM>DPTSP) ) cooling/dehumidifying and reheatin »Cool. coil cont.: IF (DPTSP>DPTSA) increase cooling or IF (DPTSP<DPTSA) decrease cooling »Heater control: IF (TSP>TSA) increase heating or IF (TSP<TSA) decrease heating Set Point (SP) Mixture 2 Mixture 3 Mixture 1 »DBT SP DPT SP

Sensible and Enthalpy and Desiccant wheels

Desiccant wheel » Figure 3 – A desiccant-based cooling system combined with regenerative heat exchanger, vapor compression cooling, and evaporative humidifier (hybrid system).

Computer software for load calculation ic/documents/marketing/hap_ehelp_009.pdfhttp:// ic/documents/marketing/hap_ehelp_009.pdf en_Chicago.pdfhttp://tc47.ashraetcs.org/pdf/Presentations/Lies en_Chicago.pdf

Residential vs. Commercial systems Course focus was on HVAC equipment that is used in both: residential and commercial systems Emphasize on the application in commercial systems

Commercial HVAC Systems Single zone Multi zone VAVCAV VAVCAV All Hydroinic that relay on infiltration With and without reheaters DOAS with fan coils or radiant ceilings With reheaters Dual duct Dual duct DOAS with fan coils With and without humidity control This is not the complete list !

Typical Components in Commercial systems Constant operation Outdoor air supply Two fans (supply and return) Multizone system Control …..

Residential Systems Buildings are responsible for 40% of US energy use ~1/2-1/3 houses There is a push for conservation in this sector Zero Energy homes ath.pdfhttp:// ath.pdf egoryID=58http:// egoryID=58

Residential System

Course objectives Apply fundamental physical principles to HVAC design Describe and size each component in an HVAC system Design HVAC systems based on manufacturer’s datasheets Contrast residential systems with commercial systems and use appropriate design techniques for each type of system Solve HVAC design problems with high-quality references