CONFIDENTIAL Technical Seminar on Application and Technical Specification 21 June 2016 Rezza Arif Bin Mustapa Kamal Senior Engineer Project And Application Department

HVAC Systems (Heating, Ventilating and Air Conditioning) Applied Product Systems (AP) Unitary Product Systems (UP) Chilled Water Air Cooled  Scroll  Modular Water Cooled  Absorption  Centrifugal  Screw  Scroll Direct Expansion (DX) Air CooledWater Cooled Split MultiSingle Packaged Split Packaged Classification of Air Conditioning System

Factors affecting the decision to select Unitary or Applied systems include:  Installed Cost  Energy consumption  Space requirements  Freeze prevention  Precision  Building height, size, shape  System cooling and heating capacity  Centralized maintenance  Stability of control  Individual tenant billing Classification of Air Conditioning System

What Is Air Conditioning? Fundamentals of Air-Conditioning

What is Air Conditioning? Air Conditioned Space temperature, humidity, cleanliness & distribution to meet the requirements of the conditioned space. It is defined as “the process of treating air so as to control simultaneously its Fundamentals of Air-Conditioning

What Is Air Conditioner? Fundamentals of Air-Conditioning

Air-conditioners are fundamentally built on the principle of refrigeration cycle which consists mainly the following components :- What is Air Conditioner? Evaporator Compressor Condenser Expansion Device Fundamentals of Air-Conditioning

Evaporator (Fan Coil Unit) The evaporator cools the air in the room by evaporating the refrigerant that passes through it. Heat is then removed from the room and is carried away by refrigerant gas …. What is the function of the evaporator? Fundamentals of Air-Conditioning

With continuous supply of refrigerant to an open system, it is inefficient and costly. ….. therefore we need a closed system Ref Air flow Fundamentals of Air-Conditioning

Basic Refrigeration System A B C D EVAPORATOR COMPRESSOR EXPANSIONDEVICE CONDENSER High pressure side Low pressure side Discharge line Suction line Liquid line Fundamentals of Air-Conditioning

Compressor Condenser Evaporator / Heat Exchanger Expansion device AIR COOLED CHILLER SYSTEM FCU AHU Water pump Chilled water P Fundamentals of Air-Conditioning

Evaporator B A Warm air Vaporrefrigerant Mixture of liquid and vapor refrigerant Function: Cool air Water condensate flows down – Absorb heat from the air that passes thru and transfer to the refrigerant and carried away Fundamentals of Air-Conditioning

Compressor Function: Low pressure vapor refrigerant from evaporator High pressure vapor refrigerant to condenser C B – Refrigerant is being compressed from low pressure & temperature to a pressure & temperature high enough to be condensed Fundamentals of Air-Conditioning

Condenser D C Warm air Liquid refrigerant to TXV Vapor refrigerant from compressor Function: Cool ambient air – Heated refrigerant gas from compressor enter the condenser, heat is being rejected to the atmosphere when cooler ambient air pass thru it Fundamentals of Air-Conditioning

– Throttle the refrigerant flow causing sudden drop of high pressure to low pressure where a flash expansion occurs that turns liquid to convert into vapor state Expansion Device (TXV) AD Function: Mixture of liquid and vapor refrigerant to evaporator Liquid refrigerant from condenser Fundamentals of Air-Conditioning

expansiondevice condenser evaporator compressor Basic Refrigeration Cycle 41.0°F[5.0°C] 51.0°F[10.6°C] D G C B E F 121.5°F[49.7°C] A 110°F[43.3°C] Fundamentals of Air-Conditioning

expansiondevice condenser enthalpy evaporator compressor Refrigeration Cycle – R410A psig pressure D G C B E F psig A Fundamentals of Air-Conditioning

Two types of heat Sensible Heat Addition of Heat = change in temperature Basics of Heat Load Calculation

Two types of heat Latent Heat Addition of Heat = change in state Basics of Heat Load Calculation

Classification of cooling load Load components can be classified into 3 categories: 1)Skin Load 2)Internal Load 3) Other Load Basics of Heat Load Calculation

Skin load for a space Ceiling & Roof / Upper Rooms Infiltration Glass Wall Ground / Lower Rooms Partitions / Inner Walls Ventilation Basics of Heat Load Calculation

Internal Load for space Equipment/ Appliances Lights People Lights Basics of Heat Load Calculation

Other load for space Duct Leakage Heat Gain Fan Heat Basics of Heat Load Calculation

heat load components in a space Basics of Heat Load Calculation

Equivalent Temperature difference method Heat Gain is given by: –Q = Rate of heat transfer [W] –A = Area of surface [m 2 ] –U = Thermal transmittance [ W/m 2 K] –ΔT = Temperature difference of wall surface(T o – T i ) Q = A x U x ΔT Basics of Heat Load Calculation

Equivalent Temperature difference method External WallsInternal Walls Roofs Ceilings Partitions Floors Q = A x U x ΔT Can be used to measure heat load for: Glass Note: This equation is used to calculate ONLY transmission gain Basics of Heat Load Calculation

Formula for u- value calculation Basics of Heat Load Calculation

Formula for u- value calculation Basics of Heat Load Calculation

Componentsb/KR [m 2 K/W]Density [kg/m3]Weight [kg/m2] Outside air film-- 12mm cement plaster 115mm brick wall 12mm cement plaster Indoor air film-- Total R:Total Weight: Example U-value calculation 115mm Brick wall + Finishes (Both Sides) 12mm thick cement plaster / / U = 1/R = 1/0.352 = W/m 2 K

Solar Gain - Glass Solar gain is given by: – Q = Rate of heat transfer [W] – A = Area of glass [m 2 ] – SF = Solar Factor [W/m 2 ] – SC = Shading coefficient of glass window Q = A x SF x SC Basics of Heat Load Calculation

Solar factor selection Reference Glass is 3 mm thick ordinary glass set in aluminium frame

Shading coefficient selection External Shading Devices: 1)Horizontal Projection 2)Vertical Projection 3)Egg-crate Lourves

Infiltration load Infiltration load is given by: – Q i = Infiltration heat load [W] – Q is = Sensible infiltration heat gain [W] – Q il = Latent infiltration heat gain [W] – V = Infiltration air volume [m 3 /h] – ΔT = Temperature difference of outdoor and indoor air – Δ X= Absolute humidity difference of outdoor and indoor air Q i = Q is + Q il Q is = 0.33 x V x ΔT Q il = 833 x V x Δ X

Cooling load calculation Summing up all of the heat load components: –Skin Load Wall, glass, floor, roof and ceiling transmission heat gain Glass solar heat gain Infiltration heat gain –Internal Load People heat Appliances Lighting –Other Load Duct leakage Heat Gain Basics of Heat Load Calculation

Heat load calculation form

Tables for heat load calculation

Heat load calculation form Tables for heat load calculation

Heat load calculation form

Rule of thumb

QUESTIONS?