Metal radiant ceilings in the tertiary sector: comfort and energy efficiency in offices and commercial spaces

1. Introduction to metal radiant ceilings in the tertiary sector

Radiant systems use large surfaces, such as floors, walls or ceilings, to heat or cool the indoor environment mainly by thermal radiation. The large heat exchange surface makes it possible to use low operating temperatures for heating (fluid temperature around 30/35°C) and high operating temperatures for cooling (fluid temperature around 18°C), thus reducing consumption and the associated costs on the energy bill, while at the same time achieving high comfort conditions thanks to the uniform distribution of the indoor temperature.

Specifically, radiant ceiling systems  have the advantage of offering maximum flexibility in the definition of interior spaces over time and can be used in both new and refurbished buildings. As they do not take up any useful floor or wall space, they offer greater freedom in the design of interiors and furnishings, making them the ideal solution for buildings that require adaptability and versatility, such as offices, commercial spaces and multi-functional structures. In addition, to perfect architectural integration, the main advantages of this technology are its high performance in both heating and cooling, low thermal inertia, absence of vertical thermal gradients, uniform comfort throughout the occupied area, easy and quick installation and quiet operation. In the field metal radiant ceilings represent an innovative and versatile solution, particularly suitable for the tertiary sector. Their low thermal inertia, their high reactivity in coping with thermal load variations, the rapidity with which they reach room temperature, as well as the ease with which they can be inspected and the possibility of integrating the typical equipment that characterises conventional suspended ceilings make them optimal for offices and commercial premises. They also offer the flexibility to interpret and change interiors over time, responding quickly to new organisational needs. Metal panels are also available in a wide range of finishes, colours and modularity. There are different types of metal radiant ceilings, which are distinguished by:

• the way in which they interact with their surroundings to transfer heat. In this case, metal panels can be classified as active, when they have the capacity for radiant heat transfer due to the integrated hydraulic circuit system, and inactive, when they have a purely aesthetic function and do not contribute to heat transfer;

• the design of the metal panels from which they are made. A distinction is made between smooth panels, which have a uniform and continuous surface, and perforated panels, which have holes in the surface that can vary in size. Perforated panels have the advantage of improving the acoustics of the room in which they are installed, making them particularly suitable for offices and meeting rooms where acoustic comfort is particularly important.

2. Designing, installing and maintaining radiant metal ceilings

Design, installation and maintenance of metal radiant ceilings require special attention to ensure effective distribution of the thermovector fluid and, consequently, temperature homogeneity, as well as high energy efficiency and system longevity. The main actions to be taken during the design, installation and maintenance phases are described below.

Phase 1: Design

The thermal requirements analysis is the first step in the design phase. This involves a precise analysis of the thermal requirements of the building, the subdivision of the internal spaces with different climatic requirements (thermal zoning), the choice of the radiant system (type of structure and panels, in accordance with the architectural choices and the specific requirements of the spaces in relation to their intended use). The second action concerns the choice of the type of distribution system and the type of materials used for joints and insulation. The next step is to plan the interaction of the radiant system with others, upstream with generators such as heat pumps, solar thermal panels, etc., and downstream with ventilation and dehumidification systems. The last phase, which is very important because it involves a joint action between the various design figures, is the integration of the various systems that must be provided in the false ceiling (lighting, air distribution, alarms, safety signs, fire protection systems, etc.).

Phase 2: Installation

The installation phase involves preparing the room: (i) checking the available space and compatibility with other systems; (ii) installing the supporting structure on the ceiling; (iii) the metal panels are then positioned, connected to the hydraulic circuit and the insulation materials are applied. At the end of the installation, a pressure test must be carried out to check that all the hydraulic connections have been made correctly. (iv) Finally, the control systems are programmed to manage the conditioning in the different rooms of the building.

Phase 3: Maintenance

Radiant ceiling systems do not require any specific maintenance in the conventional sense (replacement of components or other direct action).

However, like any system, they must be periodically checked to ensure that they are working properly.

Four different types of intervention can be distinguished for metal radiant ceilings: (i) ordinary maintenance of the ceiling, understood as periodic cleaning of the surface of the panels to maintain their aesthetics; (ii) maintenance of the hydraulic distribution, which consists of periodic inspection of the circuit to detect any leaks, checking the correct pressure and flow rates of the circuits and the operation of the circulators; (iii) maintenance of the control system, checking the functionality of the temperature and humidity sensors; (iv) maintenance of the thermal and acoustic insulation, which, in the event of damage, could reduce the efficiency of the system.

3. Integrated project with other plant systems

The synergic combination of metal radiant ceilings with other building systems is a key element that allows rationalisation of worksite and, at the same time, facilitates their maintenance over time.

In addition to the possibility of exploiting the quality of the ceiling, the system can be easily integrated with mechanical ventilation system, renewable energy sources and regulation devices that offer the possibility of dialogue with BMS (Building Management Systems) for building automation.

Coupling with dehumidification and mechanical ventilation systems

In cooling mode, radiant ceilings are responsible for balancing sensible heat loads, so it is convenient to control the indoor relative humidity by using mechanical ventilation units with high-efficiency heat recovery systems, which also featured with dehumidification function. In this way, temperature, relative humidity and indoor air quality levels are set to ensure occupant comfort and energy efficiency.

Exploiting renewable energy sources

Metal radiant ceilings can be easily integrated with sustainable generators and energy sources such as heat pumps and solar thermal collectors. This offers the opportunity to achieve excellent results in terms of energy efficiency, minimising primary energy consumption and limiting the use of non-renewable energy sources.

Controls

The integration of radiant systems with BMS and advanced thermal control systems makes it possible to optimise indoor comfort, both in winter and summer, by effectively managing air ventilation and humidity control. Specifically, the control is divided into two phases: (i) the user can set the desired comfort conditions using room thermostats (secondary regulation); (ii) on the basis of the preferences set in the thermostat setpoints, the BMS manages the operation of mixing groups, activation of the generators, air treatment and dehumidification (primary regulation). 

4. Economic and sustainability impact

The use of metal radiant ceilings in buildings helps to increase and keep their own value on the real estate market over time. The increase in financial value and market stability depends on several factors, the most important of which are:

• the higher energy efficiency that makes distinctive these systems compared to traditional conditioning systems. This feature offers the added value of reducing running costs and, consequently, energy costs for potential buyer of the building;
• the possibility of exploiting renewable energy sources helps to obtain green certifications - Leed, Well - which further increases the value of the building and makes it more competitive on the market;
• the reduced maintenance costs of a metal radiant ceiling compared to traditional systems. This is a long-term saving that makes the building more attractive to potential buyers.