Dhizaini yekapu iyi yeaizikirimu ine machira maviri inochengetedza ndiro yepepa kuti isadonhe, nepo firimu rePE rekunze richidzinga mvura nemafuta, uye firimu rePE remukati rinochengetedza muviri wekapu yepepa kuti usakanganise, zvichiita kuti igare kwenguva refu uye yakasimba.