In　cities,　there　are　thousands　of　wastewater　treatment　plants.　The　treated　tail　water　drained　from　them　is　clean　relatively,　and　has　a　stable　flow　rate.　Extracting　heat　from　it　through　tail　water　source　heat　pumps　(TWSHP)　for　space　heating　can　decrease　the　building　heating　energy　consumption　significantly.　Besides,　by　integrating　with　thermal　energy　storage　(TES),　it　can　realize　the　goal　of　peak　load　shifting,　especially　in　commercial　buildings.　However,　there　is　few　reports　on　its　experimental　investigations　or　engineering　applications　till　now.　To　promote　the　application　of　TWSHP　integrated　with　TES　system,　it　was　designed　for　the　space　heating　of　a　technology　park　in　Beijing,　and　a　control　method　was　proposed　to　decrease　the　operating　cost　by　using　the　valley　electricity.　Then,　utilizing　its　operating　parameters　in　the　heating　season　of　2021-2022,　its　heating　performance　was　analyzed.　Results　indicate　that　the　proposed　system　has　good　heating　performance.　The　average　COPs　of　TWSHP　units　and　the　system　in　the　heating　season　are　7.08　and　4.41,　respectively.　Compared　with　gas-fired　boiler,　its　carbon　emission　decreased　by　62.53%.　By　using　the　TES　system,　the　power　consumption　during　valley　period　of　power　grid　increases　by　581.23%,　realizing　the　goal　of　peak　load　shifting.