This paper presents the development of a novel method to combine measurement of local heat transfer coefficient and flow visualization in frame-and-plate heat exchanger (FPHE) simultaneously. A heat flux plate is built using two original chevron plates and clay as thermal infills. Thermocouples are deployed on the inner surfaces of both plates. With the known thickness and thermal conductivity of the clay, the instrumented plate functions as a heat flux sensor. After initial calibration, this plate is installed to measure fluid heat transfer from one side, while leaving visual access from the other. Preliminary results of water-water single-phase heat transfer and R245fa-water flow boiling are presented. Combined with visualization, the method provides a viable solution to relate local heat transfer with flow regime within a plate channel, while preserving the real geometry and operating condition. (C) 2017 Elsevier Ltd. All rights reserved.