CPD PROGRAMME
Professional development
The CIBSE Journal CPD Programme
Members of the Chartered Institution of Building Services Engineers (CIBSE) and other professional bodies are required to maintain their professional competence throughout their careers.
Continuing professional development (CPD) means the systematic maintenance, improvement and broadening of your knowledge and skills, and is therefore a long-term commitment to enhancing your competence. CPD is a requirement of both CIBSE and the Register of the Engineering Council (UK).
CIBSE Journal is pleased to offer this module in its CPD programme. The programme is free and can be used by any reader. This module will help you to meet CIBSE’s requirement for CPD. It will equally assist members of other institutions, who should record CPD activities in accordance with their institution’s guidance.
Simply study the module and complete the questionnaire on the final page, following the instructions for its submission. Modules will be available online at
www.cibsejournal.com/cpd while the information they contain remains current.
You can also complete the questionnaire online, and receive your results by return email.
This module explores the application of advanced VRV systems Evolving VRV beyond comfort conditioning
As the technology further matures, variable refrigerant volume (VRV) or variable refrigerant flow (VRF) systems are being applied to a wider range of HVAC services. Although originally designed to provide comfort air conditioning through air-to-air heat pump heating and cooling, they have evolved to encompass heat recovery systems, small (or mini) VRV systems, as well as extensive systems that can function effectively at more extreme ambient conditions – so that VRV can be used in countries with cooler and warmer climates. This CPD will consider the application
of advanced VRV systems that can provide energy and cost-effective domestic hot water, as well as fulfilling their role in comfort conditioning. VRV systems can now provide heating and
cooling to other building services, beyond the demands of direct comfort conditioning requirements. The heat pump ‘split system’, designed for heating water, was originally developed in the 1980s. By using the hot gas refrigerant (leaving the compressor), passing heat through a plate heat exchanger to a cold water supply, it was possible to heat water more effectively than using direct electrical immersion systems. However, due to the low cost of natural gas and low demand for energy- efficient products during that era, this type of heat pump hot water production system
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was not widely adopted, and manufacturing development was held back until demand increased. As technology evolved and the focus on
energy efficiency grew sharper, it became appropriate to re-introduce this technology – but not only as a split system (single indoor unit to single outdoor unit combination), but also on distributed VRV systems. Concurrently, manufacturers were also introducing direct refrigerant connections to coils in air handling units, as a means of heating and cooling ventilation air, using the refrigerant as the working fluid. Subsequently, there have been many projects that utilise VRV systems that can
control the temperature in ventilation air supplies and hot water systems. However, the success of such integrated systems requires an holistic appreciation of the building and its environment, the system (and its capabilities and practical limitations) and the operational realities. Manufacturers have the ability – and the required components – to meet the opportunities offered by VRV-linked direct refrigerant heat transfer within AHUs and plate heat exchangers, but each application needs to be carefully considered to ascertain the best system selection. Some air-handling applications lend themselves to connection to heat pump systems that are dedicated to looking after the fresh air requirements,
Figure 1: Thermal modelling of hotel March 2014 CIBSE Journal 65
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