In this post we are going to discuss in detail about the two most common and widely used HVAC systems. We are going to see the comparison between Chiller and Vrf Systems. At the beginning of planning a Heating Ventilation and Air Conditioning project, it is expected to get the task necessities, kind of utilization, obligation conditions and consistence to pertinent guidelines. To choose which cooling framework to be utilized for a specific venture, it becomes fundamental to assess different HVAC advances and frameworks that will best suit for that task. In the present world, the originator has numerous options for planning the HVAC system. and it very well may be very confounding to distinguish a right situation for a given application. To get which specific framework is the most ideal for any application, the originator needs to consider different angles, for example, life cycle cost examination, framework engineering, space accessibility, and so on.. In the present world, a typical disarray is whether to plan a framework for focal plant with chilled water framework or to utilize the Variable Refrigerant Volume System (VRF System). To comprehend the benefits and faults for every framework, let us analyze Chiller Plant System v/s VRF on various viewpoints that are for the most part considered during HVAC planning.
such as Based on Technology- what are the advantages and disadvantages of one system over another, Based on system life cycle cost analysis, Based on System Architecture, and Based on Reliablity.
First we will see based on Technology what are the advantages and disadvantages of a VRF system:
The acronym VRF stands for Variable Refrigerant Flow system. VRF in refrigeration phrasing is named as Multi Evaporator AC framework, a 'focal' air conditioning framework having limit tweak. VRF framework includes at least one number of ODUs (outdoor units), numerous IDUs (indoor units), which are associated with each other through refrigerant funneling network. The Outdoor unitss are introduced either on the roof or in the shaft space or anyplace at the helpful spot. Refrigerant is flowed through these lines, to the evaporator units. Inside spaces are cooled with the assistance of refrigerant that is flowed through evaporator units. By and large, an Electronic Expansion Valve is utilized as a development gadget. Limit regulation occurs through two major strategies - Electrical regulation - inverter based and Mechanical adjustment.
Now We will see what are some of the Advantages of Variable Refrigerant Flow systems.
Multiple Indoor Units choices can be utilized like Hi-wall indoor unit, cassette type indoor unit, concealed type indoor unit, ducted type indoor units, etc. This can help in mixing the cooling system with the proper inside plan of the space. With the current accessible choices, one can reach up to LEED-Gold rating. Activity is exceptionally straightforward, most likely, as basic as working of a split cooling system and henceforth no different labor is expected for working the framework. Great choice for giving cooling to condos/manors, little establishments where in the intricacy of the framework (a significant negative mark of this framework) can be kept to a least.
Now We will see what are some of the Disadvantages of Variable Refrigerant Flow systems.
It has a Complex framework design, enormous measure of refrigerant channeling going around in adapted space. Whenever chose to use for bigger limits, more space expected to introduce many number of
Outdoor Units. Admittance to Outdoor Units is a need, and all the support work required will be generally
on the Outdoor Units, maintenance wise. It Won't be of much advantage where the cooling load has restricted variety, for example, in IT/ITES workplaces, shopping centers, multiplexes, and so forth.. where in the variety is restricted to some gathering rooms and/or cafeterias, and so on..It Can be perilous for the inhabitants, being refrigerant flowed through pipes, powerless to spillages, with the refrigerant chance of entering the adapted space. It is Profoundly gifted work expected for establishment and charging and upkeep, particularly to recognize and address spillages. Different assessment norms are alluded for execution assessment. Constraint on CFM conveyed inside the space, up to 350CFM/TR, can be a serious constraint from indoor air quality as air flowed can be deficient.
Now We will see what are some of the Advantages of Chilled Water systems, based on Technology.
The most developed innovation with the historical backdrop of past sixty years. Global standard is alluded for execution assessment - AHRI 550/590.. Profoundly energy effective, empowers easily going along to LEED - Platinum necessities. With appropriate framework plan and introducing various chillers, even if there should be an occurrence of high variety, chillers become a decent choice because of their great effectiveness even at part load conditions. Project size isn't the requirement by any stretch of the imagination. Non-risky for the inhabitants, as water is coursed all through the refrigeration circuit, zero chance of unsafe material entering the molded space. Advantage on productivity can be duplicated by utilizing Thermal capacity; and utilization of differential plans.
Now We will see what are some of the Disadvantages of Chilled Water systems.
Accessibility of water is an absolute necessity.Water is must for this system. this system Requires extra space for plant space for chillers, Air Handling Units rooms and space for mounting the cooling towers. Prepared and well trained labor is expected for working the focal chiller plant.
Next comparison is based on Life cycle cost Analysis.
Based on many observations and case studies for a particular TR system, the life cycle cost for Variable Refrigerant Flow system is bit higher when compared to Chilled Water System. Operation and Maintenance Cost for VRF system is little higher than that of Chiller water System (for same TR capacity). Life Cycle cost can be defined as the sum of Initial CApEx, Operational cost and Maintenance Cost.
Next Comparison is based on System Architecture.
To accomplish limit adjustment, VRF framework basically requires part of electrical and electronic controls. A large portion of the controls are fitted in the Outdoor Units board. Aside from electrical-electronic controls, each open air unit comprises of refrigeration parts like blower, condenser, fan, refrigeration parts and controls, and a considerable amount of copper funneling. The framework likewise needs correspondence link to run the entire way through, from outside boxes till each and every indoor unit to trade electronic signals among Outdoor Units and each Indoor Unit. Having copper funneling, electrical cabling, correspondence links, makes the refrigeration network bit complex. Then again, water cooled screw chiller framework, engineering and its working is very basic. It doesn't need complex electrical - electronic controls, refrigeration network for the framework to work and for the limit adjustment as well. Further, course of water to the Air Handling Units is likewise an extremely straightforward framework and all the originator needs to stick to, is basic funneling rules. We as a whole know, less difficult the framework engineering, better solid it will be and better from the workableness angle as well.
Next We will compare these two systems based on their Reliability.
In Variable Refrigerant Flow systems, refrigerant is flowed all through the refrigeration circuit. Oil alongside the refrigerant leaves the blower through each blower release, which then, at that point, is circled all through the refrigeration circuits. It is extremely fundamental that anything oil that has left out of blower, ought to be gotten back to a blower, to work with grease. At low part load conditions, speed of the refrigerant and oil isn't adequately satisfactory to bring both (oil and refrigerant) back to the blower. To take the oil back to the blowers, it turns out to be generally fundamental for running the whole framework at high burden, for few moments, after each specific hours. Commonly due to the application prerequisites, the fluid line distances are very lengthy, to the tune of 400 ~ 450 plus feet. The more drawn out fluid lines further make more difficulties on account of oil recuperation. Likewise, longer the refrigerant lines, less productive the framework would be. But in case of Chillers, All chillers have an in-fabricated oil framework, consequently taking out any issues of oil recuperation.
In case of variable flow refrigerant systems, Since there is an enormous amount of refrigerant accessible in the framework, during part load conditions when just couple of blowers (matching to % part load) are in activity, the whole refrigerant mass is dealt with, by those couple of blowers. In such obligation conditions, numerous multiple times, framework might run into issues if due care isn't taken. All things considered the blowers see flooding of fluid refrigerant that ultimately prompts blower engine to wear out, mechanical breakage of the blowers, and so forth.. But in case of chiller systems, Liquid flooding isn't an issue by any means, as the framework is appropriately planned, and just the measure of refrigerant required is circled, rest stays in the condenser.
Finally from the above points we can conclude that, For more modest frameworks, up to 100 ~ 200 TR, with restricted Outdoor Units and Indoor Units, VRF framework can be a great arrangement, concerning more modest focal plant framework, space accessibility for chillers, Air Handling Units may not be accessible. Likewise, for such little frameworks, the VRF framework can stay basic with restricted refrigerant funneling and absent a lot of intricacies. But, when the establishment size begins expanding, VRF frameworks, as seen above, begin becoming perplexing and in such cases, arranging the establishment for a central plant is generally valuable. The existence cycle cost of such a framework isn't just lower than the VRF framework, however it additionally stays away from security related issues like spillage of refrigerant in adapted space, better air flow, better indoor air quality, and so forth..
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