Because district energy does not rely on electricity, building peak usage would be much lower than with VRF or installing electric units. That means that variable loads for heating or cooling would be drastically reduced—creating a flat load profile with lower demand charges.
FAQ Category: VRFs
What are the space demands of a VRF system compared to district energy?
VRF systems are normally housed on rooftops, which precludes that space from being used for building amenities, such as lounges and gardens. Additionally, there is a misconception that VRF systems do not require ductwork—though ductwork is certainly required to ensure safe air cycling in a building, especially as a result of COVID-inspired code changes to keep building occupants safe.
District energy does not require rooftop chillers or compressors, freeing up rooftop space for amenities, a solar array, or other storage or equipment needs. This also means no rooftop penetration—which can reduce risk of damage due to a compromised building envelope.
What is the electricity reliance associated with a VRF system compared to district energy?
VRF systems require electricity to run, which exposes buildings to multiple risks—including volatile electricity rates based on peak demand and policy changes that may drive those rates up in the future. And, in the event of a loss of electricity, the building would lose heating and cooling as well—which is potentially dangerous to occupants and could damage equipment and assets in the building.
District systems are a great source of reliable energy, whether heating or cooling. The robust underground steel-encased pipes of a district network are reliable even in severe weather, and district energy systems maintain 99.99% uptime. Additionally, because its central facilities are fueled by multiple sources and have bult-in redundancies, reliable district energy cooling and heating is available even in the event of electrical losses. This is critical for the wellbeing of occupants and the protection of sensitive assets and equipment, especially for mission-critical facilities like hospitals, public safety facilities or laboratories.
What type of maintenance is required with a VRF system?
VRF systems consist of multiple complex pieces of equipment which require qualified HVAC mechanics to repair and maintain. This means either keeping HVAC technicians on staff or hiring a vendor each time maintenance or repairs are required.
What capital costs are associated with a VRF system compared to district energy?
VRF systems require upfront capital costs to install. Additionally, the average life of a compressor is about 10-15 years, and they range in costs from $5k to $15k in commercial buildings. Because district energy does not require cooling or heating equipment onsite, there are typically no upfront costs associated with connecting to a district energy system—unlike the high upfront capital costs required for boilers, chillers, and cooling towers. Many district energy providers are even willing to invest in connecting a building to the district system and will cover the cost of any potential street repairs and beautification. Plus, existing ductwork in a commercial building can often be retrofitted to accommodate district energy.
What is a Variable Refrigerant Flow (VRF) system?
VRF is a refrigerant based heating and cooling system that utilizes a central outdoor condenser to feed multiple indoor evaporators. There are two main reasons a developer might choose to go with a VRF system—zoning controls and ductwork. VRF allows for more precise zoning controls, so if you need to heat or cool rooms to drastically different temperatures, VRF might be a good choice. Because VRF uses a central outdoor condenser, it also means there is less indoor equipment needed, such as separate window AC units for every room. This also keeps things quieter indoors.
