Energy-retrofitting of the Herz-Jesu church in Munich

Research project , Group project Supervisors: M. Sc. Daniele Santucci Technical University of Munich - TUM, 2014

energy-retrofitting of the herz-jesu church in munich

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Solar altitude

21/12/2013 Latitude [N]: 48.15o Longitute [E]: 11.52o

21/06/2013 Latitude [N]: 48.15o Longitude [E]: 11.52o

SUMMER FACADE

Natural ventilation (XPS) Rigid Foam Insulation

Wood frame construction wth internal shading system (maple lamella)

g-value: ca. 20% – 32% solar Control glass variable printed facade

16 mm laminated glas VSG 10 mm toughened glas ESG with low iron oxide content glas Insulated glazing (IG) (double-pane)

Natural ventilation

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Automatic tiltable windows

The Herz-Jesu church is located in Munich and was designed by Allmann Sattler Wappner Architects. The building comprises two different cubes, which are set into one another. The outer glass cube (16x21x48 m) envelopes an inner shell of more than 2.000 maple lamella. Due to the contrasting material properties of these two cubes, different colours and intensities of light shine into the church. The arrangement of the vertical lamella gradually increases the brightness of light towards the altar. At the same time, the opaque glazing prevents views into the chancel from the outside. The entrance of the building is charaterised by large, intensive blue doors, which are opened only on special holidays. The glas facade is made of doublepane solar control glass. A part of the solar radiation is reflected; another escapes into the internal space and another is absorbed from the glasa and re-emitted als heat in the space. Automatic tiltable windows, along the facade and on the top of the building, allow for natural ventilation. Underfloor convectors, along tha facade in front of the tiltable windows, heat or cool the outside air before entering into the internal space. Because of the huge glass facade, cold air drop is a major problem affecting thermal comfort, especially during the coldest months of the year.

WINTER FACADE

Natural ventilation (XPS) Rigid Foam Insulation

Cold air drop

Wood frame construction wth internal shading system (mapla lamella)

g-value: ca. 20% – 32% solar Control glass variable printed facade Heat losses

16 mm laminated glas VSG 10 mm toughened glas ESG with low iron oxide content glas Insulated glazing (IG) (double-pane)

Cold air drop

Natural ventilation when external temp.<internal temp.

Automatic tiltable windows

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Floor cooling

Underfloor heating

Chilled ceiling

Underground horizontal air ducts Heat exchanger

Heat exchanger

Ground-water heat pump

Ground-water heat pump

Chilled ceiling

Floor cooling

SUMMER 6

Primary energy demand

A heat pump provides heating during winter by extracting heat from groundwater and transferring it into the building.

A heat exchanger is in contact with the groundwater to extract or dissipate heat. In the summer, the process can be reversed so the heat pump extracts heat from the building and transfers it to the groundwater. Transferring heat to a cooler space takes less energy, so the cooling efficiency of the heat pump gains benefits from the lower groundwater temperature. Groundwater has a stable temperature of 8째C to 12째C during the whole year.

Cooling

Heating

Lighting

Floor heating

Under-floor convectos along the facade

WINTER 7

“Full operation”

“Basic operation”

Temperature measurements Date: 12/12/2013 Time: 15:00-16:00 am

The church operates ~3400 hours per year. However, there

OPTIMIZATION PROPOSAL

are two different operation types. The “Basic operation”, when the church is open for visitors but no ceremony

The optimization proposal focuses on enhancing natural

takes place and the “Full operation”, when a ceremony or

ventilation. Windows open only when the outside air

concert takes place. The desirable operative temperature

temperature is lower than the operative temperature

during “Basis operation” is ~22 °C under summer

inside the church. When the outside air temperature is

conditions and ~12 °C under winter conditions. The

higher than the inside then tiltable windows close. During

desirable operative temperature during “Full operation” is

higher cooling loads, the chilled ceiling and the floor

~19-20 °C under both summer and winter conditions.

cooling regulate internal temperatures. Underground air ducts support natural ventilation when fresh air supply

The main problem of the church is the inadequate

is not adequate through the tiltable windows. Fresh

thermal comfort, especially during the summer period.

air supply through the underground air ducts enhance

Between the glass and the wooden cube, temperature

thermal comfort especially in the space between the glass

is often outside of the comfort range. The 16m high and

and the wooden cube, Sensors regulate the opening and

48m long glass facade has no windows or openings,

closing of the windows. During winter period underfloor

which does not allow for effective natural ventilation.

convectors should be the main heating system as they

Furthermore, opening the large doors of the entrance of

are quick to heat giving convenient and instant warmth.

the church results in abrupt temperature changes, thus

For higher heating demand, underfloor heating supplies

further negatively affecting thermal comfort.

the church with additional heating.

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Underfloor heating

Convectors

WINTER

High heating load

Windows open

Higher heating demand

Natural ventilation Thermal comfort achieved

Windows open Outside temp. < Inside temp.

Chilled ceiling Higher cooling load

SUMMER Outside temp. > Inside temp.

Fresh air supply through underground horizontal air ducts Outside air temperature >26 oC

Floor cooling Windows close

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Night ventilation through tiltable windows when necessary

FACADE DETAILS

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Maria Voukia 2014

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