359
matic effects of the trees, and, therefore, far-reaching conclusions cannot be drawn
concerning their effectiveness.
Permeable Pavement Permeable pavement cannot be modelled using the ENVIMET program, thus its effects can only be estimated based on descriptive studies. It
is well known, however, that, depending on the base layer, permeable pavement is
typically able to retain 35-60 % of the water. This has several advantages. Due to its
porosity and absorbance, it warms more slowly and cools more quickly than
traditional pavement surfaces and, therefore, has a positive effect on the microclimate. It decreases storm water runoff, thus allowing water to reach the trees along
the street, and helps replenish the water Tab.. Using permeable pavement therefore
addresses two important problems of urban heat islands: it improves the radiation
and water balances.
Green Walls – Vertical Gardens For the scale of the modelling regions, the planned
green walls and vertical gardens could not be modelled; earlier research shows,
however, that green walls – vertical gardens that are nearly parallel to the direction
of the prevailing winds signifi cantly decrease mean radiant temperature (MRT) and
predicted mean vote (PMV) values in their immediate surroundings.
Green Roofs The effects of the planned green roofs are rather complex, and, therefore, diffi cult to model. Green roofs not only decrease the intensity of urban heat
islands but also decrease storm water runoff, thus also reducing the amount of greywater to be treated. They also play a signifi cant role in improving the quality of life
for people working or living in the buildings by offering a natural area for relaxation
and recreation.
Green Spaces Within the pilot area, there are two signifi cant public green spaces,
Millenáris Park and Mechwart liget, where no changes were recommended. The
model did, however, examine the effect of a new green space: the new park, to be
created at the site of a soon-to-be-demolished ministry building, which will signifi -
cantly increase the green spaces of Millenáris Park. The disappearance of the ministry block and the creation of the new green space will decrease air temperatures by
1.5–2.5 °C, according to the microclimate modelling results (Figs. 13.16 and 13.17 ).
In summary, it can be stated that within the modelled regions the microclimate –
following the localised nature of the intervention – improves in discrete areas due to
the proportionate increase of green spaces: cross-ventilation improves, relative
humidity increases, mean radiant temperature (MRT) signifi cantly decreases and, in
cases of drastic intervention, air temperatures also show signifi cant decreases.
13 Pilot Action in Budapest
matic effects of the trees, and, therefore, far-reaching conclusions cannot be drawn
concerning their effectiveness.
Permeable Pavement Permeable pavement cannot be modelled using the ENVIMET program, thus its effects can only be estimated based on descriptive studies. It
is well known, however, that, depending on the base layer, permeable pavement is
typically able to retain 35-60 % of the water. This has several advantages. Due to its
porosity and absorbance, it warms more slowly and cools more quickly than
traditional pavement surfaces and, therefore, has a positive effect on the microclimate. It decreases storm water runoff, thus allowing water to reach the trees along
the street, and helps replenish the water Tab.. Using permeable pavement therefore
addresses two important problems of urban heat islands: it improves the radiation
and water balances.
Green Walls – Vertical Gardens For the scale of the modelling regions, the planned
green walls and vertical gardens could not be modelled; earlier research shows,
however, that green walls – vertical gardens that are nearly parallel to the direction
of the prevailing winds signifi cantly decrease mean radiant temperature (MRT) and
predicted mean vote (PMV) values in their immediate surroundings.
Green Roofs The effects of the planned green roofs are rather complex, and, therefore, diffi cult to model. Green roofs not only decrease the intensity of urban heat
islands but also decrease storm water runoff, thus also reducing the amount of greywater to be treated. They also play a signifi cant role in improving the quality of life
for people working or living in the buildings by offering a natural area for relaxation
and recreation.
Green Spaces Within the pilot area, there are two signifi cant public green spaces,
Millenáris Park and Mechwart liget, where no changes were recommended. The
model did, however, examine the effect of a new green space: the new park, to be
created at the site of a soon-to-be-demolished ministry building, which will signifi -
cantly increase the green spaces of Millenáris Park. The disappearance of the ministry block and the creation of the new green space will decrease air temperatures by
1.5–2.5 °C, according to the microclimate modelling results (Figs. 13.16 and 13.17 ).
In summary, it can be stated that within the modelled regions the microclimate –
following the localised nature of the intervention – improves in discrete areas due to
the proportionate increase of green spaces: cross-ventilation improves, relative
humidity increases, mean radiant temperature (MRT) signifi cantly decreases and, in
cases of drastic intervention, air temperatures also show signifi cant decreases.
13 Pilot Action in Budapest