Rehabilitation of the Utility Spaces and

Boiler Room

Monnaie Royal Theatre, Brussels, Belgium

Dr. Eng. Ioan Silviu DOBOSI

Eng. Laura TROI

The building used for workshops andadministrative services at the Monnaie RoyalTheatre in Brussels was subjected to completerenovation, in an effort to make the workconditions for the administrative and technicalstaff at the theatre more comfortable, and thebuilding more conform to fire safetyregulations and more energy efficient.

This building, separate from the theatre itself, hastwo very different facades, a neoclassical one at23 rue Léopold (photo1) and a modernist one at41 rue Fossé aux Loups (photo 2)

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The objective of energy efficiency was achievedby renovation of the infrastructure of installations: central heating and cooling, water supply,sewage and gas pipes, electrical (power andcontrol of equipments, fire detection, lighting,and BMS (Building Management System)integration. Two major areas were asigned asutility rooms (in the basement) and the boilerroom (on the roof , 4th floor)

Hydraulic heating scheme

Hydraulic cooling scheme

The boiler room on top of the building :

Phase 1

Phase 2

Phase 3

boilers:3 x 850kW + 1x 100 kW

Main heating water distribution

Pressure maintenance system with compressors

Back of boiler: gas supply, gas exhaust , water supply and return, fresh air intake

Cooling system : • 2 x dry coolers on roof• 1 water chiller in basement

BMS (Building Management Systems) aresystems providing integrated managementof the technological functions of a building,heating, cooling access control, security,fire alarms, lights, etc.It can be accessed by remote by theadministrator, from any location, formodifying different parameters.Cabinet and display (photo)

Display BMS:Heating diagram -boilers 3 x 850 kw

Display BMS:Heating diagram -boiler 1 x 100 kw;main distribution

Display BMS:Heating diagram - hot water tank and domestic hot water supply

Display BMS:Heating diagram -supply for administration offices

Display BMS:Heating diagram -supply for workshops

Display BMS:Cooling diagram -dry coolers and water chiller

The utility rooms in thebasement of the building

Water chiller : cooling power 300 kW

The 2 Dry coolers (cooling power 195 kW / pcs) together with the water chiller from the lowest floor (the basement) make up the cooling system

Hydraulic heating scheme – version 1

Hydraulic heating scheme – version 2

When choosing the optimal solution for the heating concept, two solutions were discussed:

• Version 1 : gas condensing boilers, constant speed pumps, hydraulic pressure separator (BEP)

• Version 2: gas condensing boilers with high water content, and variable speed pumps

The second solution was implemented due to the high energetical efficiency

The issue of water properties in the heating system. Indoor old distribution versus newboiler plant . Design Requirements:

• washing facility with trisodium phosphate as a protective film against corrosion

• measuring and controlling pH, hardness, conductivity of the water

Requirement supplier of boilers:

• low conductivity - resulting pure water – filling the entire heating system old (the theatre distribution) and new (boiler plant and main distribution) with demineralised water ; it is contrary to the design requirements thusremoving the protective film of trisodium phosphate submitted to washing, in order to prevent corrosion.

Observations:1. Conductivity is determined by the presence of salts, by the

presence of sodium or NaCl (sodium chloride) used to regenerate the ion exchanger (cations).

2. The softening installation does not alter the conductivity of thewater because there is only one exchange of calcium ions withsodium ions by the ion exchanger. Therefore, the conductivity cannot be less than 800 µS / cm unless you mount a new stage ofwater purification, reverse osmosis station. In this case theconductivity drops below 80 ... 90 µS / cm, and if you mount aninstallation in two stages conductivity can be less than 10 µS / cm.

3. The presence of phosphates in the installation is caused bytraces of trisodium phosphate (Na3PO4) used in the phaseof flushing out the heating system. The presence ofphosphate ions is useful because it determines theformation of coating of iron phosphate on the inner surfaceof pipes and heating elements. This layer has a role ofprotection against corrosion.

4. The presence of ions of calcium in softened water

(~ 19 mg / L) can be determined by incomplete rinsing ofthe ion exchangers after the stage of regeneration or theexhaustion of ions in the column (in this case they should bereplaced).

In any case calcium ions are no longer present in the systemthrough the formation of insoluble calcium phosphate in water,they are deposited in the installation (but the amountsdeposited are very small - tens of milligrams per liter of waterintroduced into the installation).

THANK YOU FOR YOUR ATTENTION