Air Condition System
HVAC Design Considerations:
eMcS services offer design solutions for energy conservation oriented air conditioning systems that are duly compliant with ASHRAE, Bangladesh National Building Code (BNBC) and Energy Conservation Building Code (ECBC).
Sizing HVAC System:
We, at eMcS, understand that appropriate sizing of HVAC components is critical for the design of energy efficient HVAC system at optimum cost. Hence we adopt a systematic approach towards HVAC sizing, taking into consideration various factors such as climate, building configuration, space usage, system zoning and layouts.
Chilled Water Plants:
eMcS adopts high efficiency water cooled, low KW/TR chillers on most of the projects. Depending upon their type and capacity, large chillers are specified with variable speed drives. All the chillers are specified with microprocessor based control system along with chiller manager to monitor all the parameters of the plant. The plant generally consists of energy efficient screw chillers/centrifugal chillers/VFD driven chillers, multiple primary chilled water pumps, secondary chilled water pumps with variable frequency drives, condensing water pumps, FRP cooling towers, VFD driven double skin air handling units with thermal break and variable frequency drive, fan coil units, chilled and condensing water piping, air distribution system, insulation, electrical panels, wiring, control wiring & earthlings.
Efficient Chilled Water Distribution:
A significant amount of energy is used to distribute water for space cooling due to year round cooling loads in most parts of Bangladesh. An efficient and proper design can result in substantial operating and capital savings, and can thus have a significant impact on a building’s total energy consumption. Hence, at eMcS, the thrust is to use variable speed pumping system, a concept in Bangladesh.
Efficient Air Distribution System:
While designing the air distribution system, special attention is paid to minimize pressure drops and noise by increasing the duct size, minimizing the bends & elbows and selecting the right type of air outlets. Air distribution design options are closely coordinated with architecture/interior design keeping in view the choice of duct type. Sizing is limited by the availability of the space above false ceilings. At eMcS, duct sizing is done utilizing ducting software known as ‘Easy duct’.
Demand Control Ventilation:
High occupancy spaces have huge ventilation requirements resulting in wastage of cooling energy, when the spaces are not fully occupied. Demand control ventilation is used to estimate the number of occupants in a space and reset the ventilation rate from the design occupancy to actual occupancy. Carbon Dioxide (CO2) sensors are the only currently accepted method of demand control ventilation. The benefits of demand control ventilation are reduction in energy conservation, reduced wear & tear of the equipment and confirmed/documented indoor air quality.
Variable Air Volume (VAV) Systems:
In office buildings, shops and commercial establishments, we recommend the use of VAV’s to provide the right quantity of cool air required for a specific building zone and at the same time supply different volumes to different zones. The result is that the total supply of cool air varies over the course of the day, depending on the heat gain level in different parts of the building at different times.
Variable Refrigerant Flow (VRF) system:
VRF is a popular and cutting edge technology now-a-days. It is used widely because of its space allocation and energy conservation system and some critical indistinguishable features.
The indistinguishable features of VRF technology are –
Better part load efficiency:
VRF is capable to modulate its supply capacity to meet most indoors requirement closely integrating with the digital scroll compressor technology. This modulating capability enables the VRF system to offer higher IPLV.
No conversion lost:
Comparing to the traditional inverter drive air-conditioner VRF has eliminated the possibility of lost of energy during the conversion of power signal.
More Economical operation:
With higher IPLV, VRF is able to operate with lower power consumption.
Better dehumidifying performance:
The continuously operating compressor in the VRF system provides better dehumidifying performance and hence able to reduce the indoor RH to a more desired level. With lower RH in the interior, the growth of the Bacteria and Fungus are inhabited.
Improved Electro Magnetic Compatibility:
Unlike variable speed compressors air conditioners, VRF runs at a constant speed throughout the operation, thus there is lower electromagnetic interference. This unique feature reduces the need for expensive electromagnetic suppression electronics required to ensure electromagnetic compatibility.
Long piping design for flexibility:
Piping length between outdoor and indoor unit can be extended up to 150 meters. The height between outdoor unit and indoor unit can be extended up to 50 meters. The height difference between indoor units can be as 15 meters. This greatly reduces constraint and offers more flexibility in system design.
Tighter temperature control:
The ambient of the outdoor and indoor change frequently and this will affect the indoor cooling and heating load. With VRF system using an improved control algorithm, the temperature is kept closer to the set temperature. Comparing to conventional chilled water system, VRF required far less equipment. Boilers cooling tower are things in the past with AMDS is a better solution for new projects or even retrofit purposes.
Better place utilization:
VRF uses the single outdoor multiple indoors combination. This concept has greatly reduced outdoor units and enhances installation.
Intelligent capacity modulation:
The VRF system operates in a steeples capacity modulation ranging from 10-100% .the modulation will closely match the demand capacity whereby contributing higher IPLV.
Rapid Cooling and Heating Capacity:
The improved heat-exchanger combining with the better efficiency compressor promotes rapid exchange between refrigerant and air, ensuring set temperature to be achieved faster compared to traditional air-conditioning system.
Wider Operating Range:
VRF system undergo rigorous test to ensure that the system can operate within -15°C to 43°C.
Floor By Floor Installation:
The optional outdoor fan with external static pressure of 50 Pa is suitable for short-discharge duct work application. With this feature, an outdoor unit can be placed on each floor, thus allowing installation to be performed floor by floor.
Alarm And Diagnosis System:
The VRF system is built in with an alarm system alerting owners or users for abnormal operation, a user-friendly diagnosis system helps to identify the problems, ensuring continuous operation of the VRF system.
Adapts Easier to Any Floor Plan:
The wide indoor models can meet the needs of building size and interior design easier, incorporate with the flexible piping design, the VRF system is suitable for most type of floor layout and various applications.
After power failure, the VRF system will automatically restart operation base on the last state memory, setting of the unit will not be lost, thus eliminating the needs for re-programming.
CO Sensors for Car Park Exhaust:
Basement car park ventilation is often provided with exhaust fans to operate during normal occupancy hours. In accordance with ASHRAE Application Handbook, with reduction in vehicle emission, lower ventilation rates may be considered while designing the ventilation system for car parks. Accordingly, we recommend fans to be provided with VFD’s which are actuated through CO Sensors based on the level of CO concentration, thus resulting in substantial energy savings.
Total covered cooling capacity will be calculated follows the standard. This cooling load will be served by roof top chillers plant room or Floor wise modular system. Chiller will be screw compressor type and containing automatic chilled water balancing system to maintain the exact cooling and pressure to the FCUs of the different floors. Central monitoring system will be involved in this central Air Conditioning System. So that from the central control room can observe the any FCUs run/Stop status and can also be controlled on/off of any FCUs. Each FCU have local temperature monitoring system and chilled water modulating system so that the system will be perfectly energy saving system as required by international demand.
We are dedicated for making Design, Drawing, BOQ and Tender document, Tender Evaluation, supervision of Semi-Central and Central Air Condition System. We are also designing Clean room air condition design for pharmaceutical, Lab, Operation theater etc. We strictly follows international standard and recommendation as SMACNA, ASHRAE, AHRI (ARI), NFPA, BNBC and BS.