The paper investigates the energy conservation properties of two well-known projection-based particle methods, namely, MPS and ISPH methods. The enhancing effects of a set of refined schemes including Higher order Source term (HS), Higher order Laplacian (HL), Error Compensating Source (ECS), Dynamic Stabilizer (DS) and pressure Gradient Correction (GC) are shown through the simulations of a standing wave, oscillating drop and impacts of two fluid patches. The results highlight the superiority of corrected Taylor series consistent pressure gradient models for projection-based particle methods in providing accurate results with the best energy conservation as well as accurate reproductions of physical dissipations in fluid impact problems.