Home / Energy efficiency / Case Study-Retrofitting of old buildings

Case Study-Retrofitting of old buildings

Print Friendly, PDF & Email

Globally, businesses, national and local governments and property owners have begun to retrofit many older buildings in a bid to cut down on energy use and reduce greenhouse gas emissions

Retrofits are the most cost-efficient ways to combat climate change and save on rising power bills, according to analysts ranging from the McKinsey Institute to the International Energy Agency.

A retrofit program can:

• Significantly reduce utility costs resulting in significant savings

• Give measurable return on investment typically recouping the cost of the program within a few years

• Reduce system repair and maintenance costs

• Improve occupant comfort and overall health, thereby reducing occupant complaints

• Increase energy efficiency

• Reduce risk of costly repairs

• Increase productivity

• Enhance Safety

The building, Capemisa, is located in Botafogo neighborhood in the city of Rio de Janeiro with approximately 40m high and 4000m² of built area.

Before the retrofit, the building’s HVAC system equipment was performed by direct expansion type ‘self-contained’ condensing to water distributed by the existing twelve-story building. To meet the necessity of condensing equipment, two towers located on the roof condensation provided water for all equipment in the building.

Due to ravages of time, a project was developed for retrofit installations of the building, keeping 90 workstations per floor, meeting rooms, support rooms and common areas fully modified.

To retrofit the building’s air-conditioning, the HVAC consultant adopted the direct expansion system of the gas, using the DRI EcoFresh enthalpy wheel model equipment that has the technology of Variable Refrigerant Flow (VRF) and air condensation, allowing modulation of capacity in each individual indoor unit by varying the flow of refrigerant gas to meet the real needs of the thermal load of the system. Installation of this air-conditioning system is aimed to provide thermal comfort throughout the year with individual control of temperature, which can be triggered by remote control or through local or central control system with the use of system monitoring and automation installed in the building.

The Consultant used refrigerant R-410A which is already a new generation, Being environmentally correct, it does not harm the ozone layer.

Always thinking in energy efficiency of the system and the possibility of using the heat exchanger air-to-air due to the large amount of outside air required for the system, the HVAC consultant adopted the use of heat recovery enthalpy wheel ensuring insufflation of air from outside, doubly filtered according to the recommendations of the ABNT norms. The system is designed to operate according to the following conditions:

• Temperature of dry bulb air intake – 36.2 º C

• Wet bulb temperature of air inlet – 27.5 º C

• Temperature of dry bulb air return – 26oC

• Relative humidity of return air – 55%

• Flow insufflation – 42,529m³/h

• Flow Rate of Return – 40,388m³/h

• Total pressure of the air supply fan – 650Pa

• Total pressure of the fan feedback – 600Pa

The stove consists of the enthalpy wheel and fans blowing and exhaust air.

Leave a Reply