Monitoring confirms efficiency of Passive House indoor pool

Details to be presented at International Passive House Conference in April
Jan. 30, 2014

Darmstadt/Germany. The municipal swimming pool operator in the German city of Lünen ventured into unchartered terrain when it decided to build its indoor swimming pool to the Passive House Standard some years ago. This courageous step has now paid off, as the monitoring results show. The savings in terms of energy consumption, for heating as well as for electricity, are substantial compared with other swimming pools. The monitoring carried out by the Passive House Institute also shows that even further optimisation is possible during the building’s use. The beacon in Westphalia thus forms an outstanding basis for subsequent projects. Details on this will be presented by Jessica Grove-Smith from the Passive House Institute at the International Passive House Conference in Aachen, taking place from 25 - 26 April 2014. A general article on the energy efficiency in indoor swimming pools is now available online on Passipedia.

Hallenbad Lünen Innenansicht
Passive House windows provide for a high level of energy efficiency. Photo: PHI

Swim­ming pools are ex­tremely en­ergy-in­tens­ive. Since many swim­ming pools in Ger­many were built in the 1970s, there is a great need for re­fur­bish­ment on a broad scale. "There is a huge po­ten­tial for sav­ings – and the data from Lün­en clearly shows that Pass­ive House is a prac­tic­able solu­tion here as well", ex­plains Søren Peper, sci­en­tif­ic ad­vi­sor at the Pass­ive House In­sti­tu­te. By build­ing to the Pass­ive House Stand­ard, hun­dreds of towns and mu­ni­cip­al­it­ies can re­duce their run­ning costs.

One of the key re­quis­ites for achiev­ing the Pass­ive House Stand­ard, also in the case of in­door swim­ming pools, is a high qual­ity build­ing en­vel­ope, in­clud­ing the glazed areas. This not only helps sig­ni­fic­antly im­prove thermal com­fort, but also al­lows for the pool to be op­er­ated at high­er levels of in­door air hu­mid­ity without caus­ing con­dens­a­tion. High­er levels of in­door air hu­mid­ity means re­duced evap­or­a­tion from the wa­ter sur­face, thus res­ult­ing in lower heat­ing re­quire­ments for the pools.

Fur­ther sav­ings can be achieved with the vent­il­a­tion sys­tem. Heat losses are re­duced by the use of high qual­ity heat ex­changers and ad­ap­ted vent­il­a­tion reg­u­la­tion. Smal­ler air quant­it­ies and the use of en­ergy-sav­ing devices provide for sig­ni­fic­antly lower con­sump­tion. Im­proved swim­ming pool tech­no­logy with en­ergy-ef­fi­cient elec­tric­al sys­tems and re­cyc­ling of fil­ter back­wash are oth­er key as­pects in this concept.

Sci­en­tif­ic mon­it­or­ing of the pro­ject in Lün­en star­ted early on in the plan­ning pro­cess. The Pass­ive House In­sti­tu­te ini­tially pre­pared a baseline study in 2009. The res­ults were dir­ec­tly in­cor­por­ated in­to the design and the most im­port­ant find­ings of this pro­cess, in­clud­ing the first en­ergy bal­ances, were pub­lished in a re­port by the in­teg­rated design team. In Septem­ber 2011, the "Lippe-Bad", a sports swim­ming fa­cil­ity with five sep­ar­ate pools, fi­nally opened its doors. The en­ergy flows in­side the build­ing were sys­tem­at­ic­ally re­cor­ded and ana­lysed for over a year up un­til March 2013.

As it is of­ten the case with com­plex new builds, the meas­ure­ment peri­od was marked by the ad­just­ments of the build­ings sys­tems. Nev­er­the­less, the val­ues for the fi­nal en­ergy con­sump­tion were still with­in the pre­dicted range, based on a pool area of 850 m², heat­ing re­quire­ment of 1189 kWh/(m² a) and elec­tri­city re­quire­ment of 718 kWh/(m² a). Al­most 12 per­cent of the elec­tri­city con­sump­tion was gen­er­ated through sol­ar en­ergy.

In the fu­ture, it will be pos­sible to re­duce the fi­nal en­ergy de­mand for the "Lippe-Bad" even fur­ther, es­pe­cially by means of the sys­tem for pro­cess­ing the fil­ter back­wash which was not in op­er­a­tion dur­ing most of the mon­it­or­ing peri­od. Fur­ther sav­ings are ex­pec­ted with ref­er­en­ce to the elec­tri­city de­mand. Like the "Bam­ba­dos" swim­ming pool in Bam­berg which was built at around the same time, this pi­lot pro­ject thus proves that even in the case of swim­ming pools the ef­fi­ciency of the Pass­ive House concept is a mod­el for the fu­ture. The com­plete mon­it­or­ing re­port and stud­ies re­lat­ing to the plan­ning are also avail­able on Pas­si­pe­dia.

Gesamtansicht Passivhaus-Hallenbad in Lünen
Full view of the Passive House swimming pool in Lünen near Dortmund, open since 2011. Photo: PHI
Entrance area of the new "Lippe-Bad"
Entrance area of the new "Lippe-Bad", which boasted more than 200.000 visitors in 2012. Photo: PHI
Optimised indoor air humidity reduces heat emission due to evaporation. Photo: PHI

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