To　reduce　building　energy　consumption　and　solve　the　problem　that　the　power　of　traditional　exhaust　air　heat　pump　is　limited　by　exhaust　air　volume,　an　innovative　fresh　air　and　indoor　air　co-treatment　parallel-loop　exhaust　air　heat　pump　(CPEAHP)　was　proposed,　and　three　operating　modes　of　the　CPEAHP　were　studied.　The　results　showed　that　the　co-treatment　mode　not　only　increased　the　flexibility　of　system　regulation,　but　also　improved　the　heating　performance　of　the　system　at　low　temperature　in　winter.　When　the　winter　outdoor　temperature　was　higher　than　0　°C,　the　temperature　efficiency　of　the　co-treatment　mode　was　higher　than　100　%,　and　that　efficiency　was　higher　than　100　%　under　all　outdoor　temperature　conditions　in　summer.　At　a　winter　outdoor　temperature　of　−15　°C,　the　co-treatment　mode　could　increase　the　temperature　of　fresh　air　by　20.4　°C　and　increase　the　temperature　of　indoor　air　by　3.1　°C,　the　heating　capacity　of　the　system　was　6.3　kW　and　the　COP　was　8.7　at　this　time.　At　an　outdoor　temperature　of　42　°C　in　summer,　the　co-treatment　mode　could　decrease　the　temperature　of　fresh　air　by　22.8　°C　and　decrease　the　temperature　of　indoor　air　by　3.1　°C,　the　cooling　capacity　of　the　system　was　7.3　kW　and　the　COP　was　4.5　at　this　time.　These　results　demonstrated　the　excellent　performance　of　CPEAHP　system,　and　the　application　of　CPEAHP　system　was　expected　to　reduce　building　energy　consumption　and　promote　carbon　neutrality　in　the　construction　industry.　©　2024　Elsevier　Ltd