Chowotchera mapaipi ndi zida zopulumutsa mphamvu zomwe zimatenthetsa poyambira. Imayikidwa pamaso pa zida zotenthetsera sing'anga kuti zitenthetse sing'anga mwachindunji, kuti zizitha kuzungulira kutentha kutentha kwambiri, ndikukwaniritsa cholinga chopulumutsa mphamvu. Amagwiritsidwa ntchito kwambiri potenthetsera mafuta amafuta monga mafuta olemera, asphalt, ndi mafuta omveka bwino.