Building Air Conditioning System: Office Rental
The selection of the appropriate building air conditioning system for the building is very important, it must meet all the requirements and requirements of the building in terms of indoor climate, must promote the advantages, and limit the disadvantages. points, ensuring economic optimization, operating with high reliability, easy operation, maintenance, long service life, etc. In addition, user requirements are also very important.
Office building air conditioning system
Normally, for high-rise office buildings, it is mandatory to have a central air conditioning system to cool the entire space inside the building. To design the air conditioning system in this case, the designer usually gives two options: the refrigerant air conditioning system is water (Chiller system) and the refrigerant air conditioning system is Gas (VRV, VRF system, Multi…). So what are the differences and advantages and disadvantages of these two systems? We would like to give an overview analysis for readers to understand as well as choose suitable for their works.
A Chiller system is an air conditioning system that generates cold water and uses this cold water as a carrier to carry heat to the cooling devices. The system includes a water chiller (chiller), indoor heat exchangers (FCU, AHU), a plumbing system, a water pump, an electrical system, a control system, and other ancillary systems… The chiller cools the water, and the water is pumped to the indoor heat exchangers (FCU/AHU) through the water pipeline system. At FCUs/AHUs, the air in the room is cooled after exchanging heat with cold water in the unit. The water after passing through the FCU/AHU returns to the chiller and continues the cycle. Water chiller – chiller – can be air-cooled or water-cooled. When the chiller is water-cooled, the system will have an additional cooling cycle for the chiller including a water cooling tower, cooling water pump, and cooling water piping system.
Central air conditioning system (VRV, VRF, Multi…) is composed of one or smaller systems, each of which includes 1 outdoor unit (hot unit) connected to many indoor units (refrigeration unit). ) through a gas pipeline and control system. The outdoor unit has the effect of cooling, the indoor unit has the effect of cooling the air in the room. The inverter air conditioning system is different from the single-parent multi-child air conditioner (1 outdoor unit and many indoor units) in that: in a single-parent air conditioner, each indoor unit is connected to the outdoor unit by a gas pipeline. individual; In inverter air conditioners, the indoor units are connected to the outdoor units by a common gas pipeline.
There are many factors that affect the decision of which air conditioning system to choose and the choice will be based on the advantages and disadvantages of the two systems as well as the characteristics of the building. Here we would like to compare the main advantages and disadvantages of the two systems to give the readers the most overall view.
Machine connection distance
The water refrigerant is transported to the FCUs and AHUs through a pump and pipeline system. How far it can be transported is completely dependent on the pump’s thrust capacity, and in theory, the pipeline can be extended indefinitely because additional pressure pumps as well as intermediate cold storage tanks can be created. Meanwhile, the gas refrigerant transported to the indoor units is completely dependent on the compressor located Outdoor. The compressor capacity cannot be infinitely high, which means that the indoor units cannot be placed too far from the outdoor unit (usually for air conditioning systems running using gas, the maximum height difference between the outdoor unit and the indoor unit is usually in the range of 70-90m, the maximum distance is about 200m). Therefore, for buildings over 25 floors, if using a gas refrigerant air conditioning system, it is imperative to arrange a separate space to place the outdoor unit called a technical floor to reduce the height difference… This is not a problem for systems using water refrigerant (Chiller) because only need to arrange a small space to install a booster pump that can lead cold water to any desired height.
Power capacity and utilization factor at the same time
Currently, inverter technology has come to life as an effective energy-saving solution, it has been widely applied in many appliances for life and air conditioning equipment is no exception… Inverter technology was first applied to air conditioners by Daikin Japan and the VRV brand was born. Later, most air conditioners using gas refrigerants developed product lines using inverter technology such as VRF (Toshiba), SETFREE (Hitachi), MULTI V PLUS (LG) … or using technology. Recent digital technologies such as DVM (Sansung), DIGITAL (York)… With a history of more than 100 years of development, the air conditioner product line using water refrigerant also recently applied inverter technology to product components. products (VSD) such as inverter compressors, inverter pumps, and inverter fans… and thus significantly improved the product’s power consumption.
Theoretically, products using water refrigerant have higher effective power consumption (kW/ton, COP, EER) (i.e. more economical) than systems using refrigerants. gas refrigerant load. However, due to the complex structure as well as the materials must have high durability, the products using water refrigerant are often produced with large and very large capacities (several tens to several thousand tons of cold) while the products using the water refrigerant are often produced with a large capacity. Products using gas carriers are not more than a few tens of tons of cold. When the system is in operation, if the demand is not high, the gas refrigerant system will be more economical (due to subdividing into small systems) but when the demand is high (full load), the quality system will Water cooling is dominant. This is why the concurrency factor is included as a major consideration. If the concurrent utilization factor is high (e.g. halls, shopping mall floors, gymnasium…), then the water chiller system will be suitable, and vice versa when the concurrent utilization factor is high. low (for example, small office areas, functional independent spaces with a small area…) than a gas refrigerant system will be suitable.
Installation space of building air conditioning system
As analyzed above, the water carrier air conditioning system usually has a large capacity while the gas loading air conditioning system has a much smaller capacity. Therefore, when designing an air conditioner for a large building, the number of outdoor units of the gas refrigerant air conditioning system will be many and will require a lot of installation space, respectively. If the building has many floors, it is imperative to arrange many outdoor space areas and that will waste a lot of office space (used as a technical area) while for the refrigerant system For water, only one space is enough, the chiller can even be placed in the basement, which is very convenient for operation, maintenance as well as saving installation costs.
Flexibility, usability, and connectivity
Chiller systems are designed for areas with a large coefficient of concurrency, which means that the flexibility of this system is not high. Assuming that due to the needs of users, they only want to cool a small area (for example, just rent a small counter in other areas that have not been rented or cool a small meeting room outside office hours), then it is clear Water refrigerant system will take a lot of electricity to operate the whole system. For gas refrigerant systems this is not a problem.
When put into use, the chiller water conditioning system will be forced to operate according to a complicated process whether it is turning on or off and it means having a trained technical team. created to understand and operate the system. While for the gas refrigerant system, the user simply needs to operate the remote control to operate the indoor unit without any training. This is clearly the superiority of the gas refrigerant system.
Normally, Chiller air conditioning systems are usually whole assemblies, and durable components, so they are much less damaged than gas-powered air conditioning systems. However, when a problem occurs, the repair time of the Chiller is relatively long, and the affected area (not cool) is large. Meanwhile, for a gas-powered system, due to the small capacity of the outdoor unit, if there is a failure, the affected area that is not cool will be much smaller. Moreover, for gas-powered systems, there is often a backup mode, which further minimizes the negative impact on the cooling load when a failure occurs.
Today’s technology is more and more modern, and the requirements for automation are increasing as well as the requirements for use and management are increasing, so the air conditioning system also needs to meet high technical requirements such as: connected to the BMS building management system, capable of controlling and managing via the internet, capable of calculating electricity consumption to each separate space… This is an undeniable advantage of the control system. refrigerant gas refrigerant compared to other air conditioning systems.
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Q: What are the legal requirements for lease contracts in Vietnam?
Vietnam has specific legal requirements for lease contracts, such as registration with the local authority and the inclusion of certain clauses, including those related to rent adjustment, termination, and dispute resolution.
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There are several types of lease contracts available in Vietnam, including commercial office leasing, co-working space lease contracts, and business center lease contracts.
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An office lease contract is a legally binding agreement between a landlord and a tenant, which sets out the terms and conditions for renting office space.