The product service system (PSS), as a design concept for integrated products and services, needs to be evaluated in the early design stage to maximize the value for stakeholders of the PSS concept, which is a crucial task for enterprises. However, existing methods focus on the ranking and value assessment of PSS evaluation criteria (e.g., quality, sustainability, cost), ignoring the needs conflict between customer value and economic objectives in PSS design, resulting in decision results that are not applicable to industrial enterprises. Furthermore, the influence of weight preference and uncertain information on solution evaluation is seldom considered when calculating the weight of each criterion. To fill this gap, integrating rough sets and the Shapley value decision approach for product-service system design considering customer value-economic objective trade-off is proposed, which mainly includes two parts: firstly, the best worst method (BWM) and the entropy weight method are integrated to obtain the comprehensive weight of evaluation criteria in the customer value and economic objectives; secondly, the Shapley value method in the coalition game is used to solve the optimal expectation allocation of the two objectives, so as to select the solution closest to the allocation, i.e., the optimal solution. In addition, rough set techniques are used to capture and integrate subjective assessment information originating from DMs under uncertainty. Finally, a case study of the electric forklift design is illustrated to verify the proposed decision model. The decision results show that this approach is more reliable through sensitivity and comparison analysis, and provide a valuable recommendation for enterprises to consider product service in forklift design.

A new design of high thermal efficiency gas stove which can effectively utilize waste heat of the stove has been proposed by directing at the low thermal efficiency problem of existing open combustion-type gas stoves. Based on practical product investigation, technical methods including introduction of closed furnace body design, adding of waste-heat utilization heat exchanger and design of gas premixing device are applied by aiming at heat loss of imperfect gas combustion caused by open combustion, heat loss taken away by high-temperature flue gas, and heat loss produced by flame radiation and convection in the open space, so as to effectively improve the thermal efficiency of gas stove. The thermal efficiency experiment of model machine has verified the effectiveness of this design.